modify WELS_CLIP1 to be inline functions
remove unncessary cast
Rename the asm subdirectories to x86

This is consistent with having the arm assembly in a subdirectory
called arm.
Use __APPLE__ instead of APPLE_IOS for using the apple cpu feature detection
Use __APPLE__ instead of APPLE_IOS in the arm assembly sources
Merge pull request #532 from huili2/WELS_CLIP1

Modify MACRO WELS_CLIP1 as inline functions
Merge pull request #537 from mstorsjo/rename-x86-asm

Rename the asm subdirectories to x86
Merge pull request #538 from mstorsjo/use-apple-builtin-define

Use __APPLE__ instead of APPLE_IOS for apple/arm specific features
reoranize common to inc/src/x86/arm
add missing build files
Merge pull request #540 from licaiguo/reorgcommon-pr

reorganize common to inc/src/x86/arm