build-sys: Remove version number from installed files

When packaging a new version for OpenEmbedded, I use the buildhistory-diff tool to check what changed between the versions. The version number in the module directory and in the libpulsecore and libpulsecore libraries means that I get tons of diff output due to changes in file paths. In the wall of file name changes it's hard to see if something else than just the version number changed.

That motivated me to write this patch. I don't think there's any good justification for having the version numbers in the file names. We don't support installing two different versions in parallel anyway, so what other reason could there be for the version numbers? My guess is that the version number indicates that the library/module isn't compatible with any other version, but I don't think that is a very strong justification for the extra hassle.

Makefile.am becomes cleaner too without the version number in library names.