Merge "Move SAD and variance functions to common"

vp8/common/arm/armv6/vp8_sad16x16_armv6.asm

vp8/common/arm/armv6/vp8_variance16x16_armv6.asm

vp8/common/arm/armv6/vp8_variance8x8_armv6.asm

...common/arm/armv6/vp8_variance_halfpixvar16x16_h_armv6.asm

...ommon/arm/armv6/vp8_variance_halfpixvar16x16_hv_armv6.asm

...common/arm/armv6/vp8_variance_halfpixvar16x16_v_armv6.asm

vp8/common/arm/neon/sad16_neon.asm

vp8/common/arm/neon/sad8_neon.asm

vp8/common/arm/neon/variance_neon.asm

vp8/common/arm/neon/vp8_subpixelvariance16x16_neon.asm

vp8/common/arm/neon/vp8_subpixelvariance16x16s_neon.asm

vp8/common/arm/neon/vp8_subpixelvariance8x8_neon.asm

vp8/common/arm/variance_arm.c

vp8/common/postproc.c

vp8/common/ppc/sad_altivec.asm

vp8/common/ppc/variance_altivec.asm

vp8/common/ppc/variance_subpixel_altivec.asm

vp8/common/sad_c.c

vp8/common/variance.h

vp8/common/variance_c.c