common: properly report clang compiled by version
cmake: add install targets, machine generate x265.def and x265_config.h

Now X265_BUILD is maintained in just a single place, souce/CMakeLists.txt.

The shared library is only installed if a valid tag is found; meaning the user
must be building a Mercurial clone or a release tarball with .hg_archive.txt
file in it (otherwise they must install the shared library themselves)

--HG--
rename : source/x265.def => source/x265.def.in
cmake: nit cleanups in version.cmake
cmake: enable vim syntax hightlighting
cmake: add uninstall rule for non-Windows platforms

CMake on Windows doesn't appear to generate an install manifest file
api: add exported strings which describe version and build info

It seemed more useful for this data to be in the x265 library rather than the
CLI app
asm: adopt x264 CPU detection and flags
ipfilter: move 16bpp primitives into a separate area of the file

This isolates the remaining vector primitives from the intrinsic primitives
testbench: repair --cpuid command line argument
primitives: show capabilities used even when cpuid is specified
vec: it seems clang has its own set of intrinsic generation bugs

If clang is allowed to run the instrinsic functions it builds in these two files
it causes SEGVs
cabac: cleanup TEncBinCoderCABACCounter to reduce C++ feature
cabac: cleanup unused code
cpu: disable -Wnarrowing for cpu.cpp

This C99 code from x264 causes warnings when compiled for C++
slicetype: fill in missing detail from slicetypeDecide()

This moves slicetypeDecide() to make the file more readable. It also adds stubs
for features that we do not support yet including weightp, B-pyramid, intra
refresh, user-supplied slice types, etc
common: sanity check some lookahead settings