moved lens distortion code from bpgl to vpgl
updated lens distortion comments
removed extra braces
made vpgl_algo a top level section
moved subsubsections up to subsections
added initial sections on radial distortion
Merge branch 'dev/move-lens-distortion-to-core'

* dev/move-lens-distortion-to-core:
  added initial sections on radial distortion
  moved subsubsections up to subsections
  made vpgl_algo a top level section
  removed extra braces
  updated lens distortion comments
  moved lens distortion code from bpgl to vpgl

Conflicts:
	contrib/brl/bbas/bpgl/tests/CMakeLists.txt
	contrib/brl/bbas/bpgl/tests/test_driver.cxx