add .tmp directory to git ignore
add .tmp directory to git ignore

This is where files are copied to during the Gulp production build
process.  It should be deleted automatically at the end of the process,
but we’ll add it just in case so it doesn’t accidentally get committed.

CCI-MOC/GUI-Frontend,CCI-MOC/GUI-Frontend,CCI-MOC/GUI-Frontend,CCI-MOC/GUI-Frontend,CCI-MOC/GUI-Frontend