use large/medium/similar to define scene change result
fix the condition of scene change flag and comments
Avoid clobbering the registers q4-q7 in DeblockingBSCalcEnc_neon

Remap q5 to q8, q6 to q9, q7 to q10 and q8 to q11, and push
q4 to the stack.

This was missed previously since the codec unittest doesn't
test encoding with loop filter enabled yet.
Add encoder tests with deblocking and/or denoising

This increases the coverage of assembly routines (and encoder
features in general) tested by the codec unit test.
Use -DPREFIX instead of --prefix _ on OS X

The --prefix parameter differs between yasm and nasm; nasm
requires --prefix _ while yasm requires --prefix=_. Using the
define instead (as on windows) allows easier switching between
the two otherwise mostly compatible assemblers.

This fixes building with yasm on OS X in 32 bit mode. For 64 bit,
a few more tweaks are still required.
Use the SIGN_EXTENSION macro where possible

This shortens the x86 assembly by 134 lines in total.
Merge pull request #501 from mstorsjo/neon-register-backup

Avoid clobbering the registers q4-q7 in DeblockingBSCalcEnc_neon
Merge pull request #496 from mstorsjo/use-sign-extend-macro

Use the SIGN_EXTENSION macro where possible
Merge pull request #483 from volvet/develop_b

use large/medium/similar to define scene change result
Merge pull request #503 from mstorsjo/encoder-test-coverage

Add encoder tests with deblocking and/or denoising
Remove commented out code for old, 32-bit only x86 assembly function prologues/epilogues
Merge pull request #515 from mstorsjo/remove-commented-x86-asm

Remove commented out code for old, 32-bit only x86 assembly function prologues/epilogues
Use movsxd in SIGN_EXTENSION

This is what nasm ended up assembling movsx with 32 bit input to
anyway.

Keep using plain movsx for 16 bit input.

This fixes building with yasm in 64 bit mode.
Fold ALIGN 16 and the function label into WELS_EXTERN

This simplifies the structure for all x86 assembly functions,
reducing the amount of duplicated code structure.
Remove commented out rodata sections and tables in assembly files
Merge pull request #508 from mstorsjo/fix-yasm-osx

Use -DPREFIX instead of --prefix _ on OS X
Merge pull request #518 from mstorsjo/remove-commented-rodata

Remove commented out rodata sections and tables in assembly files
Don't clobber q4-q7 in WelsIntra16x16Combined3Satd_neon

This is similar to what is done in other neon functions. This
function was missed since it isn't covered by the current
set of unittests.
Enable the arm assembly in msvc-arm builds

This requires using the external gas-preprocessor tool that
converts the gnu assembler format sources to armasm format at
build time. This allows keeping the source files in one single
format but only converting while building.
Merge pull request #521 from mstorsjo/neon-register-backup

Don't clobber q4-q7 in WelsIntra16x16Combined3Satd_neon