Fixing cally.pc.in and moving include headers to previous directory

Fixing cally.pc.in and moving include headers to previous directory

After commit 8dd8fbdb some errors appear if you try work directly
against cally:

 * cally.pc.in removed some elements. After install clutter, doing
   pkg-config --cflags cally-1.0
   fails due missing winsys

 * cally headers were moved from clutter-1.0/cally to
   clutter-1.0/clutter/cally.  Applications using it (yes I know,
   nobody is officially using it) would require to:
    * Change their include.
    * Add directly a dependency to cally, in order to use the cally.pc
      file with the correct directory include.

Note: Take into account that accessibility support still works (ie:
clutter_get_accessibility_enabled). This bug only prevents
applications to work directly against cally (ie: create a CallyActor
subclass)

http://bugzilla.clutter-project.org/show_bug.cgi?id=2353

Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>