Add decomposition tests

These tests pass IF you run them one at a time, due to an
existing bug in decomposition with memory mangement. I'm
adding this to ensure no regressions for the next fixes.
Fix a memory management bug

Don't assign back to the passed data matrix!
Using np.sqrt is about 5 times fast than power

Also, always put decimal places for floating point division!
Forgot a decimal point on the power
Add the inplace keyword and update the docstring

Still need to make sure that our PCAModel uses this keyword
by default!
Set inplace kwarg in PCAModel
find what files menpo can import in glob
Merge remote-tracking branch 'upstream/master' into decomposition_fix
Remove auto generation
Let's use a new prettify extension

This changes all verbose references to pretty ones!
Let's try out the new package layout

This gives an example of how the image documentation will
look!
Use full path so that autogenerated links work
Adds str and trim by variance to pca.

- Reimplements noise_variance property, and adds some convenient properties related to variance
OK some TOC trees for our classes

Missing all individual pages
IO module docs
Landmark docs
Math docs
Model docs
Wrong link in model docs, fixed
Add rasterizer docs