COMP: Added new unit tests for increasing code coverage

Added new testing code for TriangleMeshToBinaryImageFilter,
ErodeObjectMorphologyImageFilter,
SignedMaurerDistanceMapImageFilter,
SignedDanielssonDistanceMapImageFilter,
DoublThresholdImageFilter,
MorphologicalGradientImageFilter

Change-Id: I15eed6a350d1d49cfdbbdd0587a85821a766ecdd
ENH: Add OnePlusOneEvolutionaryOptimizerv4 to ITKv4 registration

OnePlusOne evolutionary optimizer is converted from the ITKv3 to v4 registration
framework. A test is designed for this newly converted optimizer
and is passed successfully.

Change-Id: I836c3de67f180320435a8ffa95b1672def44090f
Merge topic 'OnePlusOneOptv4'

d048b97c ENH: Add OnePlusOneEvolutionaryOptimizerv4 to ITKv4 registration
Merge topic 'CodeCoverage'

c6afaa88 COMP: Added new unit tests for increasing code coverage