MultiChannelShading: Fix 4 compiler warnings

git-svn-id: https://valelab.ucsf.edu/svn/micromanager2/trunk@14591 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd
Log an error when we fail to start live mode.

For example, if the sequence buffer is larger than 3GB in 32-bit mode.

git-svn-id: https://valelab.ucsf.edu/svn/micromanager2/trunk@14592 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd