Documentation clarifications for map and bimap folds.

library/bimap.m:
	Specify that foldl over a bimap is done by inorder traversal
	by key.

library/map.m:
	Likewise for foldl_values and map_foldl.
Update some documentation.

.INSTALL.in:
	Binaries for GCC and friends are also included with MinGW.

README.ThreadScope:
	We don't require a separate copy of the project (and Paul's)
	contact details here.
Update more web and email addresses.

LIMITATIONS:
doc/mercury.info.in:
	As above.
Update REAMDE.MS-VisualC:

README.MS-VisualC:
    Mercury has been ported to 64-bit Windows, just not when
    using MSVC as a C compiler.
More documentation updates.

.README.in:
	The contents of java/runtime come under the LGPL as well.

	Minor rewording.

README.MS-Windows:
	We don't need to list every version of Windows we no longer
	actively support.  (If the version is not on the list of those
	we *do* support, then we don't support it.)

README.MacOS:
	We will never support compiling Mercury with llvm-gcc on
	Mac OS X 10.5 and 10.6.