Unify the codepaths for WELS_GET_PERFIX_BITS at the second place

This changes a second use of the macro which was missed in
60e0255677.

This avoids warnings about unused local variables in 64 bit
builds in MSVC.
Fix parsing of the -drec option if ENABLE_FRAME_DUMP isn't set

If the define wasn't set, the argument iterator didn't skip
the file name argument.
Remove sad.asm from the processing lib, move satd_sad from the encoder to the common lib

sad.asm as used in processing is an exact subset of the
code in satd_sad.asm in the encoder.
Remove an unused assembly source file

Nothing within processing uses functions from this file.
Merge pull request #252 from mstorsjo/share-processing-asm

Merge identical assembly code between the processing and encoder libs
Merge pull request #247 from mstorsjo/simplify-missed-inline-asm-macro

Unify the codepaths for WELS_GET_PERFIX_BITS at the second place
Merge pull request #249 from mstorsjo/encconsole-arg-parsing-ifdef

Fix parsing of the -drec option if ENABLE_FRAME_DUMP isn't set
Merge remote-tracking branch 'upstream/master' into travis.osx