Evaluation altorithms separated from misc

Created a new nipype.algorithms.eval group for methods performing
simple error, distance or similitude computations over images.

I think this is better than having them mixed up with, e.g.,
nifti or csv files management.

I also add a new interface: ErrorMap, that computes a distance
function between two images (e.g. two displacement fields). Several
metrics will be available, however now I contribute only with
squared differences maps.
Added masks support in ErrorMap interface
more informative message
added squeeze of 1 comp dimensions
Fixed error forming an extension of a filename
Fixing errors to attend #830
Minor changes to satisfy #830
Backwards compatibility in #830
Updated CHANGES
Moved the new Similarity in 4D to metrics

Close #802. Please merge #830 before this PR
updated changelog
Added version 0.10.0 to all DeprecationWarnings
Fetch upstream and Merge branch 'master' into enh/EvaluationAlgorithms

Conflicts:
	CHANGES
Merge branch 'enh/Similarity4DMetrics' into enh/EvaluationAlgorithms

Conflicts:
	CHANGES
Fixed test in new Similarity interface

Also fixed constructor of old interface to throw the DeprecationWarning
Added package_check for nipy in new Similarity4D

Additionally, docstrings have been improved for several methods,
especially indicating deprecated classes.
Improvements on ErrorMap implementation

Now it uses numpy.linalg.norm
Merge pull request #830 from oesteban/enh/EvaluationAlgorithms

Evaluation algorithms separated from misc