expensive properties should really be methods
face_normals from property to method
pseudoinverse, aligned_soource move to properties
av_aligned_error -> mean_alignment_error GPA
adds daisy features
adds daisy tests
Merge pull request #470 from jabooth/methodsproperties

expensive properties should really be methods
Fix from_mask for Trimesh subclasses

Handle masking tcoords and colours for textured/coloured
trimeshes
Merge pull request #473 from patricksnape/from_mask_fixes

Fix from_mask for Trimesh subclasses
adds _daisy.py in external, changes default params
removes visualization from _daisy.py
Merge pull request #472 from nontas/daisy

Daisy features
adds normalize norm and std in Image class
Merge pull request #475 from nontas/normalize_image

Normalize norm and std of Image object