Implements #183 depth ray correspondences

Some improvement work to do:

• hole fill estimates
• tune parameters
• add normal checks

added 11 commits

• 61d7ccdf - Add mask channel and mask wrapper
• 9446e473 - Remove old energy vector
• 39d53443 - Attempt at hole fill
• 61146e59 - Allow disable of filling
• 6c5ea3a2 - Mess with confidence channel
• a5838f17 - Selection of cost functions
• 94463ca7 - Inline cost functions
• 928c70b4 - Tidy code
• 53c0517c - Fix visualise confidence
• f9cbd639 - Improve confidence render
• 3478218d - Minor change

Compare with previous version

added 5 commits

• 8a5fe815 - Revert to best cost
• 4375393c - Colour confidence
• 965dd96d - Fix missing breaks
• ccbd22c2 - Improved confidence
• 6327e630 - Minor changes

Compare with previous version

merged