Revert "core: Make interest points repeatable"

This reverts commit 8db46f445ec5da02fe0b4d1ae0dfbc3df7a36063.
all: use parallel ip desription

Hopefully this will speed up DG ip description.
stereo_pprc: Added cache aware rendering of subsampled images

This should change our render access patterns so that we hit cached
tiles more often.
Core: stereo_pprc: Use separable convolution

Our AA filter previously accessed all the pixel manually and repeated
a lot of calculations. This version uses a separable convolution.
orthoproject: Minor robustification
Documentation: Update for seed-mode 2 and some clarifications
StereoSessionIsis: Minor comment rewording
Sessions: More specific debug output stream
Stereo: Compute D_sub based on DEM settings and initial work
DG: Remove duplicate code
DG: Minor comment removal
stereo_tri: use smart pointers
stereo: Low-res disparity: Use tiling
D_sub from DEM: Implement faster LM solver by seeking over ray
TestStereoSessionDG: Minor adjustment
LinescanDGModel: Use uncorrected as initial guess
stereo: cleanup in low-res disparity code
RPCModel: Rm caching of initial guess for thread safety
stereo_corr: Add disparity spread when computing disparity from DEM
stereo:User safety check applies for RPC as well. Other cleanup