Clean up module item caches.

The product- and project-specific ones were left-overs from earlier
concepts, so get rid of them. Everything goes into the same "global"
cache now. Also make sure that we cache disabled modules too; the
respective files were always re-read from disk so far.

Change-Id: Ib1dee08dbbfe61b0369772df96122e8eab19741b
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Version bump.

Change-Id: Ie511b180a525fa889ff425414cb8c344c902e4fe
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
cpp module: Make library symlink artifact creation dynamic.

Currently, the build graph artifacts for symbolic links to a dynamic
library (such as libfoo.so.1.0) are always created, even if the library
does not have a version number. They get then merged with the actual
library artifact due to the identical file path, which is weird.
Instead, create such an artifact only if the corresponding symbolic link
will really be created by the command.

Change-Id: I6af903132560b1ea6ebd4f0d073a37cf845e7533
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>