Rename fittings to fitting_results
Adds initialization by bounding box.

As a by pass of this:

- perturb_shape becomes a public method on Fitters.
- fit_images disappears from Fitters
Improves documentation
Fixed align_shape_with_bb
Changes fit in SDMs to the have the new syntax.

- defaults verbose to False
remove map_coords, mayavi standard dep, gitignore
__init__.py still had multivariate_normal
remove multivariate_normal from docs
Fixes bug in pca related to noise variance computation
Adds DX, DL, DP, along with documentation.

This commit simply adds the classes. Nothing is changed in the source.
Adds tests for PCAModel.

Tests for:
- changing n_active_components
- trimming
- variance coherence and variance coherence after the previous two
Merge pull request #324 from jabooth/diffstaged2

Adds DX, DL, DP, along with documentation.
Merge pull request #330 from jalabort/pca_variance_trim_tests

Adds some tests for PCAModel
Forgot self in fit method of SDM
fixes _str_ of AAM class
Merge remote-tracking branch 'upstream/master' into rmmultivar

Conflicts:
	menpo/model/pca.py
Merge remote-tracking branch 'upstream/master' into fitter_framework_fixes
Merge pull request #306 from jalabort/fitter_framework_fixes

Flexible initialization for Menpo Fitters
Merge pull request #321 from jabooth/rmmultivar

remove multivariate_normal hack, mayavi standard dep, gitignore
adds n_training_images to AAM object