libwebsockets

Fixed CMake compile options.

Fixed so that the build options for the CMake project works:

- The test apps used the LWS_NO_EXTENSIONS define, so they needed lws_config.h included when building using CMake.
- Rename some options so that individual test apps can be turned off.
- Separate building the test-client/test-server and compiling the server/client parts into the lib.
- Don't include server or client specific sources into the build if they shouldn't be built.
- Added an error if both client and server parts are excluded at the same time (makes no sense).
- Removed duplicate install targets for the test apps.
- Commented out the WITH_LIBCRYPTO option since it isn't used at the moment.