Bug 1014955 - [Camera] Migrate v1.3T downsampling patches to v1.4/master

Contains the following ported patches from 'v1.3t' for new, refactored Camera app on 'master':

Bug 989290
https://github.com/mozilla-b2g/gaia/commit/708cfea86d5db38e8adfc9fcc7593f7ef55d1a61

Bug 1001724
https://github.com/mozilla-b2g/gaia/commit/630d955e8471afb7410cd7cfb2fbe40b213ab175

Bug 1006882
https://github.com/mozilla-b2g/gaia/commit/d00f5eb018d0df3495b96ab83f760c5a1f96fff6