pc_align: Added --semi-major-axis and --semi-minor-axis options
stereo_tri: Minor clarifications
Docs: Clarify what the universe radius does
docs: Minor clarifications about pc_align
docs: Clarify more about universe center
pc_align: Write to vw_out, not cout
point2dem: Fix for large memory use
Core: Altered InterestPointMatching affine check to allow flipped images
Core: Added some documentation to several classes