Description of problem:
Exporting a large TMX takes some time, and a warning is given to the user to expect this. Importing a Translation Memory takes much longer, but lack this warning.

Version-Release number of selected component (if applicable):
Dev

How reproducible:
Easy always

Steps to Reproduce:
Pre: Any tmx file, larger ones are the problem
1. Go to Administration, Translation Memory
2. Press Import (create a new one if empty)
3. Select a large file
4. Press Upload

Actual results:
Goes straight into uploading

Expected results:
It should warn, eg "This may time some time. Are you sure you want to import $file?"

Additional info: