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.