Debian fixes - Githubissues

minor fixes for things i find tedious while preparing a (tentative) Debian package

a number of files are marked as executable (mostly .cpp and .h)
shebang missing from a helper-script (I only discovered this as a false-positive while trying to get rid of those executable resource files)
remove the $PWD from DESTDIR to allow proper out-of-tree builds (#25)

grame-cncm / faustlive