refactor the setting of function pointer for simplification
Add Unit Test Expand Picture
add static
 add maxbitrate parameter
rephrase blockzero function complexity and remove useless functions
Merge pull request #552 from dongzha/ExpandPic

Add Unit Test Expand Picture
Merge pull request #550 from sijchen/funcptr_refactor

[Encoder Refactor] Simplify the setting of function pointers
Merge pull request #554 from ruil2/encoder_update

 add maxbitrate parameter
Merge pull request #555 from huili2/remove_unused_func

rephrase blockzero function complexity and remove useless functions
expand MVD table and rename some macros
add leve parameter, update profile and usagetype type
Merge pull request #557 from sijchen/me_refactor4444

[Encoder Refactor] Expand MVD table
Merge pull request #558 from ruil2/encoder_level

add leve parameter, update profile and usagetype type
Merge remote-tracking branch 'upstream/master' into travis.osx