add entry for '-resize' option in cwebp's man

Change-Id: I04b2853825527b03cfa73377004b1a2a40b4c94f
Demux: Correct the extended format validation

Earlier "f = f->next_" was executing for both inner and outer loop, thus
skipping validation of some frames.

Change-Id: Ice5cdb4ff5da78384aa0573addd3a5e5efa0b10c
add a 'format' field to WebPBitstreamFeatures

Change-Id: I79a688e4c34fb77527127bbdf4bc844efa6aa9a4
add missing const

Change-Id: Id1c767d21d52197ed2e4497005eb9c4795c602f0