Description of problem:
Cura cannot read STL files.

Version-Release number of selected component (if applicable):
cura-lulzbot-3.2.23-1.fc27.noarch

How reproducible:
Always

Steps to Reproduce:
1. Add STL to the build plate
2.
3.

Actual results:
Traceback

Expected results:
No traceback

Additional info:
I tried various STL files. Maybe the problem is in the python library.

2018-10-31 11:43:17,074 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [82]: Exception: Exception occurred while loading file /var/tmp/fedora.stl
2018-10-31 11:43:17,075 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: Traceback (most recent call last):
2018-10-31 11:43:17,076 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib64/python3.6/site-packages/stl/stl.py", line 75, in load
2018-10-31 11:43:17,076 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     fh, header, speedups=speedups)
2018-10-31 11:43:17,076 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib64/python3.6/site-packages/stl/stl.py", line 218, in _load_ascii
2018-10-31 11:43:17,076 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     return _speedups.ascii_read(fh, header)
2018-10-31 11:43:17,077 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "stl/_speedups.pyx", line 120, in stl._speedups.ascii_read (stl/_speedups.c:2641)
2018-10-31 11:43:17,077 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: RuntimeError: (1, "Can't read normals (2:b'facet normal -0.97951 -0.201395 0')")
2018-10-31 11:43:17,077 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: 
2018-10-31 11:43:17,078 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: During handling of the above exception, another exception occurred:
2018-10-31 11:43:17,078 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: 
2018-10-31 11:43:17,078 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: Traceback (most recent call last):
2018-10-31 11:43:17,078 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib/python3.6/site-packages/CuraLulzbot/UM/FileHandler/ReadFileJob.py", line 66, in run
2018-10-31 11:43:17,079 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     self.setResult(self._handler.readerRead(reader, self._filename))
2018-10-31 11:43:17,079 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib/python3.6/site-packages/CuraLulzbot/UM/Mesh/MeshFileHandler.py", line 28, in readerRead
2018-10-31 11:43:17,079 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     results = reader.read(file_name)
2018-10-31 11:43:17,079 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib/uranium-lulzbot/plugins/FileHandlers/STLReader/STLReader.py", line 56, in read
2018-10-31 11:43:17,080 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     self.load_file(file_name, mesh_builder, _use_numpystl = use_numpystl)
2018-10-31 11:43:17,080 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib/uranium-lulzbot/plugins/FileHandlers/STLReader/STLReader.py", line 35, in load_file
2018-10-31 11:43:17,080 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     self._loadWithNumpySTL(file_name, mesh_builder)
2018-10-31 11:43:17,080 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib/uranium-lulzbot/plugins/FileHandlers/STLReader/STLReader.py", line 87, in _loadWithNumpySTL
2018-10-31 11:43:17,080 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     for loaded_data in stl.mesh.Mesh.from_multi_file(file_name):
2018-10-31 11:43:17,081 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib64/python3.6/site-packages/stl/stl.py", line 355, in from_multi_file
2018-10-31 11:43:17,081 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     raw_data = cls.load(fh, mode=mode, speedups=speedups)
2018-10-31 11:43:17,081 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib64/python3.6/site-packages/stl/stl.py", line 81, in load
2018-10-31 11:43:17,081 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     name, data = cls._load_binary(fh, header, check_size=False)
2018-10-31 11:43:17,081 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:   File "/usr/lib64/python3.6/site-packages/stl/stl.py", line 108, in _load_binary
2018-10-31 11:43:17,082 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]:     count, MAX_COUNT)
2018-10-31 11:43:17,082 - ERROR - [(140276450457344)-Thread-8] UM.Logger.logException [86]: AssertionError: File too large, got 2019914866 triangles which exceeds the maximum of 10000000