Fix default setting of ALSA hardware volume. This worked earlier, but it broke after we added alsa-plugins-pulseaudio to the chroot to allow localapps to use sound. alsa-plugins-pulseaudio redirected the default ALSA output to pulseaudio instead of hardware. Impact: It was impossible to increase volume to an audible volume with most hardware. Fix: Add -c0 to calls to amixer so it directly sets the first ALSA hardware device. All hardware channels are increased from 55% to 90% by default. WARNING: This triples the default software volume and will be a big surprise if your speakers are maxed out. ltsp-5.1.55 will be the first build with this new behavior. You must update ltsp-client in the chroot.