ENH: Renamed ZeroTargetCheck target to ZERO_CHECK for consistency with other CMake-generated targets (ALL_BUILD, RUN_TESTS, INSTALL).

ENH: Removed cmMakefile arguments from cmTarget methods because cmTarget has the ivar m_Makefile now.  Re-implemented cmLocalUnixMakefileGenerator3::AppendAnyDepend to use the new global knowledge and avoid the need to look at the cache for information about other targets.  This should fix problems with custom commands and executables with the OUTPUT_NAME set.  Also the <target>_LIBRARY_TYPE cache variable is no longer needed at all and has been removed.

ENH: Added support for parallel builds in VS 8.  There is now a special target on which all other targets depend that re-runs CMake if any listfiles have been changed.  This addresses bug#2512.

ENH: Add a way for the generated command to include extra flags. This is useful for CTest (or try compile) to add -j2

ENH: Add variable for debugging. This variable CMAKE_PARENT_LIST_FILE holds the parent CMake list file of the current cmake list file.