BUG#891: When building CMake itself, use the new cmake to install so that the current cmake can be overwritten.

a) new version of tools like Doxygen and Graphviz now set install path info in win32 registery. use it.
b) remove DOT_PATH, it was polluting the cache (can be computed from DOT, update CMakeLists.txt accordingly if DOT_PATH is not defined)

BUG: undo last bug fix because it breaks cmake, rebuild_cache on ParaView gets tons of errors about not being able to create the bin directory

ENH: Fix bug in cmake install when exec/librayr output path not defined. Closes Bug #899 - subdir INSTALL_TARGETS INSTALL_PROGRAMS dont work

BUG: When creating a test driver, do not remove the old file, so if nothing changes, it will not rebuild. Fixes Bug #885 - cmCreateTestSource overwrite file when running cmake