AliInst: nicer error if git-new-workdir not found
AliInst: removed SVN garbage
AliInst: same user can run many installs at once

Log files have current Bash PID prepended for uniqueness
AliInst: fixed -maxdepth position in AliEn cleanup
AliInst: Bash cleanup
AliInst: support Clang on Linux!
AliInst: full compiler paths, do not rely on $PATH

This works around an error in the Vc module in AliRoot, but it is
also a general good practice.
AliInst: honor compiler flag for FastJet
AliInst: honor compiler for FJContrib too