ENH: add ability to set installer icons, links to web pages, nsis code in the icon section of the template, and ability to escape variables correctly

Alex

CMAKE_FIND_PREFIX_PATH is both an environment variable and a cmake variable,
which is a list of base directories where FIND_PATH, FIND_FILE, FIND_PROGRAM
and FIND_LIBRARY will search in the respective subdirectories

Alex

BUG: Fix bug#5590.  When converting a relative path between two full paths on different windows drive letters do not create a ../../d:/foo/bar path and just return the full path to the destination.

to make them actually work

Alex

ENH: change to make the documentation class more generic, about halfway there, also provides secitons for Variables now

ENH: change to make the documentation class more generic, about halfway there, also provides secitons for Variables now

ENH: do not remove executables and dll's before linking them so that incremental links work, incremental links are still broken for vs 2005 and greater because of the manifest stuff