Shared lib and fix delayed list identity

Hi,

thanks to @SharifuddinAmin and @wpmccormick two things have been added since the last release.
First @SharifuddinAmin found and fixed a bug in the delay time for delayed list identity messages, which resulted in no wait time in most cases. Now the behavior should be correct. Thanks!

@wpmccormick shared his CMake files for building OpENer as a shared library. This is done by setting the CMake variable BUILD_SHARED_LIBS to true. Please note, that there is no variable generated for the GUI. You have to either supply it via command line or add it by hand in the CMake config. A better documentation is now pending, but will be delivered later on.

Thanks again and please report bugs and suggest new features for OpENer!

Best regards,
Martin