Use 3-tap spatial filter in FILTER_INTRA experiment

3-tap recursive intra prediction filters are added.
Macro USE_3TAP_INTRA_FILTER is set to 1 to use 3-tap by default.
Coding gain of FILTER_INTRA experiment in AWCY, high delay 150f
3-tap: 0.51%
4-tap: 0.68%

Change-Id: I44192dd08bfd8155f58a9b0b5cf1de88fceb762e
4 files changed