cmake updates

* require cmake 3.0
* support AppleClang (MATCHES instead of STREQUAL)
* fix clang version regex
set Boost_ADDITIONAL_VERSIONS

* so we're not relying on someone from CMake project updating FindBoost.cmake
* https://github.com/Kitware/CMake/commit/ca90709fd67dc0a83ca6f75d793eab38967745a3
* NOTE: 1.57.0/1.57 isn't on the list, yet