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 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
Merge branch 'master' of https://github.com/cisco/openh264 into me_refactor3
reformat