rdcost: use less fractional bits for lambda scale, and larger ints for chroma

This fixes really bad mode decisions made with some Main10 encodes that were
apparently caused by integer overflow
fix g_chromaScale for 420 videos accordingly to the HEVC spec.
interlace: set sourceScanType to 0 to indicate interlaced video
interlace: set sourceScanType to 0 to indicate interlaced video
Added tag 1.0 for changeset cea97c4d7945
Merge with stable
use fseekg() to skip frames for 64bit builds

This is orders of magnitude faster, at least on Windows, than repeated calls to
ignore(framesize)
cmake: add a clean-generated Makefile rule

'make clean-generated' will remove all the machine generated files in the build
folder so that they will be re-generated with more up-to-date version info the
next time you run 'make'

The "easy" workaround for this problem is to just nuke the build folder and
start a new one.