fix clcache.py to work with vs2008: read/expand cmd line parameters as utf-16 from input files referenced with '@'
revert changes to cl.exe invocation
redo changes to compiler invocation: pass original parameters to cl.exe
Merge remote-tracking branch 'frerich/master', knowingly overwriting all my changes to clcache.py.
Merge remote-tracking branch 'jonastr/master'

I think I incorporated all the improvements done into this branch in my own
master branch by now, so let's do a merge with '--strategy ours' so that I can
see that I got all the work done here just by looking at the commit graph.