libwebsockets

Added CPack support + some more.

- "make dist" will now produce a tar.gz file. This includes everything (not really what we want but a start).
- Got rid of a bunch of defines and variables that aren't used.
- Added the option LINK_TESTAPPS_DYNAMIC that enables linking to the shared library version of the lib for the test apps, instead of doing it statically like the default is.
- Fixed proper support for the --prefix stuff (-DCMAKE_INSTALL_PREFIX for cmake). (Don't specify /usr/local explicitly, that is the default anyway and will break other platforms).

- Note: I noticed a problem with the "INSTALL_DATADIR" define used by the test-apps. Since we hard code the path to the certs using this, doing "DESTDIR=/bla make install" will result in not being able to use the SSL mode for the test-apps since they won't find the certs. (This also applies to the autoconf project). Fixed this by setting "../share" as the default location instead of using the prefix.