Add FindHg module to find Mercurial

Also teach the CMakeOnly.AllFindModules to verify Hg version detection.
ExternalProject: Add Mercurial (hg) repository support

Add options HG_REPOSITORY and HG_TAG to specify an external project
hosted in a Mercurial repository.  Teach ExternalProject to clone the
repository and update from it.  Extend the ExternalProject test to try a
Mercurial repository when hg is available.
CMake: Clarify the documentation for if(f1 IS_NEWER_THAN f2)

...comparison operator in the IF command. In the event of
a tie, we intentionally return "true" so that dependent
build operations are guaranteed to occur until one file
is definitively newer than the other file.

A tie means we're not sure, so return true to be on the
safe side.
DeployQt4:  Include DESTDIR for some cpack generators.
Merge topic 'deployqt4-destdir' into next

1e3248c DeployQt4:  Include DESTDIR for some cpack generators.
Add -DNDEBUG to RelWithDebInfo flags where where Release flags had it.

Previously, it was inconsistent in that some platforms/compilers
had this flag for the RelWithDebInfo configuration and some didn't.
This fixes issue #11366.
Merge topic 'relwithdebinfo-consistency' into next

0ddfc51 Add -DNDEBUG to RelWithDebInfo flags where where Release flags had it.
Merge topic 'clarify-if-is_newer_than-docs' into next

0eaaa86 CMake: Clarify the documentation for if(f1 IS_NEWER_THAN f2)
CMake Nightly Date Stamp
Merge topic 'hg-modules' into next

b9954f2 ExternalProject: Add Mercurial (hg) repository support
ea5bfb1 Add FindHg module to find Mercurial
ExternalProject: Use hg 1.1 repository format
Merge topic 'hg-modules' into next

885c5d2 ExternalProject: Use hg 1.1 repository format
ExternalProject: Add Mercurial (hg) repository support

Add options HG_REPOSITORY and HG_TAG to specify an external project
hosted in a Mercurial repository.  Teach ExternalProject to clone the
repository and update from it.  Extend the ExternalProject test to try a
Mercurial repository when hg is available.
Merge topic 'hg-modules' into next

91053cd ExternalProject: Add Mercurial (hg) repository support
FindQt4: Give precedence to QTDIR environment variable, if set.

Remove old search paths that aren't needed.

Keep using PATHS instead of HINTS because a Windows machine may have
a different Qt in its PATH and putting QTDIR and the registry entry
ahead of PATH could cause apps to fail when run.
Merge topic 'qt4-path-search' into next

35c6ae8 FindQt4: Give precedence to QTDIR environment variable, if set.
Convert the CPACK_CYGWIN_PATCH_NUMBER variable to a cache variable

Makes it easy to override it, by priming the cache from a release
build script, for example.

Also: correct mistaken @@ variable references with plain ${}
style references so that future readers do not think that it
must be an input to configure_file...
Eclipse on OSX: fix handling of framework include dirs (#13464)

On OSX, the output from gcc looks like this:
 /usr/include/c++/4.2.1
 /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64
 /usr/include/c++/4.2.1/backward
 /usr/lib/gcc/i686-apple-darwin10/4.2.1/include
 /usr/include
 /System/Library/Frameworks (framework directory)
 /Library/Frameworks (framework directory)
End of search list.

The "(framework directory)" part needs to be removed so that Eclipse handles it properly

Alex
Eclipse on OSX: improve handling of framework include dirs (#13367)

It seems that if cmake finds something like the following:
/System/Library/Frameworks/GLUT.framework/Headers
Eclipse doesn't like that and wants to have
/System/Library/Frameworks
instead

Alex
Merge topic 'HandleMacFrameworkIncludeDirs_13465' into next

9110d0e Eclipse on OSX: improve handling of framework include dirs (#13367)
d97b385 Eclipse on OSX: fix handling of framework include dirs (#13464)
c4306dc CMake Nightly Date Stamp