preset: For ultrafast preset, turn off lft, change rdLevel from 3 to 2.

This adds about 20-25% more performance for ultrafast presets at little efficiency cost.
preset: set superfast, veryfast, faster and fast presets to rd 2.
TEncSearch: use actual frame thread count to decide motion search limits

--HG--
extra : rebase_source : a2d983a1b1085230b8bdd0f0dfbd86195b8e9592
Disable exceptions for all compilers which support fno-exceptions

--HG--
extra : amend_source : c420c8e2312036bed314e4d38da8d3d68ea8d429
cmake: move all "GCC-like" logic together, use consistent var names
cmake: encoder.cpp no longer needs -Wno-unused-parameter
cmake: nit
rc: improve visual quality in high bit depth encodes.
fix to support multiple color space format in TComSampleAdaptiveOffset and TEncCu structure
TEncCu: nits
add support for lossless encode

--lossless forces full lossless coding of every frame and every CU.

--cu-lossless forces the encoder to perform RD cost analysis between lossy and
lossless modes and choose the least cost mode for each CU.
change license email globally
psy: use m_lambdaSAD multiplier for psy cost, m_lambdaSSE for bits

in x264, m_lambdaSSE = lambda2, m_lambdaSAD = lambda
TEncSearch: remove unnecessary pragma
refine cbf==0 path: remove clearing coeff and resi
primitives: move more aliasing to Setup_Alias_Primitives
TEncSearch: rename variable to avoid shadowing an earlier 'part'