BUG: Do not require language flags variables.  Other generators do not, and it breaks programmable language support (like the Java test).

ENH: Split CMAKE_STANDARD_LIBRARIES into per-language variables CMAKE_<lang>_STANDARD_LIBRARIES.  This is needed to get programmable language support working with Visual Studio generators.  It makes sense anyway.

ENH: Added support for multiple outputs generated by a single custom command.  For Visual Studio generators the native tool provides support.  For Xcode and Makefile generators a simple trick is used.  The first output is considered primary and has the build rule attached.  Other outputs simply depend on the first output with no build rule.  During cmake_check_build_system CMake detects when a secondary output is missing and removes the primary output to make sure all outputs are regenerated.  This approach always builds the custom command at the right time and only once even during parallel builds.

BUG: Add target-level COMPILE_FLAGS to the target not the individual source files.  This simplifies the generated files and puts flags in a more logical order (VS6 works, VS7 needs more translation to work).

ENH: If CMAKE_NO_AUTOMATIC_INCLUDE_DIRECTORIES is not set try to approximate in-source build include file behavior in an out-of-source build by adding the build tree directory corresponding to a source tree directory at the beginning of the include path.  Also fixed VS6 and VS7 generators to use cmLocalGenerator's computation of include paths.  The VS6 generator will now short-path the include directories if the total length is too long in order to try to avoid its truncation limit.

BUG: Avoid adding unused rules to special targets like ALL_BUILD.  Make sure project regeneration rules go only in desired targets.

ENH: Enabled new WORKING_DIRECTORY option to ADD_CUSTOM_COMMAND and ADD_CUSTOM_TARGET on VS 6 generator.

fix many bugs related to target names being computed inconsistently.

- Centralized computation of a target's file name to a method in
  cmTarget.  Now that global knowledge is always available the
  *_CMAKE_PATH cache variables are no longer needed.

- Centralized computation of link library command lines and link
  directory search order.

- Moved computation of link directories needed to link CMake targets
  to be after evaluation of linking dependencies.

This also removed alot of duplicate code in which each version had its
own bugs.

This commit is surrounded by the tags

  CMake-TargetNameCentralization1-pre

and

  CMake-TargetNameCentralization1-post

so make the large set of changes easy to identify.

ENH: for all custom commands that can not be given to a target, add them to all targets in the current makefile

BUG: Fixed OUTPUT_NAME feature for VS6 generator.  It was not working for Debug builds and was not paying attention to the executable output path.

BUG: Fixed ordering of multiple commands in a custom target when implemented as custom commands.  Also added support to execute pre-build rules first to be consistent with makefile generator.

ENH: big change that includes immediate subdir support, removing the notion of inherited commands, makefiles no longer read in the parent makefiles but instead inherit thier parent makefiles current settings

BUG: Replaced previous fix with an implementation of properly formatting the custom build code in the generated file.

ENH: Converted some ConvertToRelativeOutputPath calls to ConvertToOptionallyRelativeOutputPath in preparation for making ConvertToRelativeOutputPath always convert.  Some of these might be able to be switched back but we will first have to test what paths can be relative in the generate VS project files.

ENH: Updated implementation of custom commands.  Multiple command lines are now supported effectively allowing entire scripts to be written.  Also removed extra variable expansions and cleaned up passing of commands through to the generators.  The command and individual arguments are now kept separate all the way until the generator writes them out.  This cleans up alot of escaping issues.