Changed feature computation
Adds a faster n-dim k-channel version of extract

Note this needs some more testing. Perf was higher before making it
n_dim - is this worth the trade off?
Merge branch 'master' into faster_sdm
Merge remote-tracking branch 'upstream/master' into faster_sdm
Merge remote-tracking branch 'upstream/master' into faster_sdm
Fixes and improves extract_local_patches_fast
Merge branch 'master' into faster_sdm

Conflicts:
	menpo/fit/regression/trainer.py
Merge branch 'master' into faster_sdm
Fixes previous merge
Fixes edge cases for extract_local_patches_fast
Merge remote-tracking branch 'upstream/master' into faster_sdm
Fixes bugs for SemiParametricClassifierBasedRegressorTrainer
Attemps at fixing the previous errors introduced to SDCLMs
Changes back build_sampling_grid
Vectorizes extract_local_patches
Back to SDCLMs original version
Merge remote-tracking branch 'upstream/master' into faster_sdm
Last fixes
fixes sdm_test_1
HOTFIX: ram requirements for AAMs bug

The reference frame was getting damaged when calculating the
RAM requirements, this fixes this.