Split the nghttp2 library into objects and a shared library from those
objects. This is needed because of symbol visibility. An advantage over
the autotools build is that there are no worries about static versus
static library builds.
Test:
cmake $srcdir
make nghttpx-unittest main failmalloc
make test
Add auto-detection to the most important features (app, hpack, etc.).
Move options to a separate file for easier search.
Add cmake-based Libevent, jansson and CUnit search. Move pkg-config
handling for Libev and jemalloc to their cmake files.
Note: duplicates find_package before including CMakeOptions.txt and when
checking for features. Maybe that can be cleaned up later...