CMake: Add support for CAPNP_LITE version of kj to support MSVC builds.
CMake: Update CMakeLists with MSVC compiler flags and paths.
CMake: Remove redundant MSVC test.

CMake automatically patches the switch character.
MSVC: Qualify `std::initializer_list` to fix name lookup when compiling 'iostream-test.c++'.
CMake: Fix paths to gtest libraries for the Xcode generator.
CMake: Reduce MSVC warning level
CMake: Simplify gtest library paths and use the default MSVC CRT flags.
Merge pull request #154 from pqu/cmake

CMake support for MSVC/Visual Studio