[m2448] Add CMake source groups to target 'shared'

This is the exact same grouping as it is currently in the VC 2012 files.

Based on cmangos/mangos-classic@2467ab8c48

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>
[m2449] Add CMake source groups to target 'framework'

This is the exact same grouping as it is currently in the VC 2012 files.

Based on cmangos/mangos-classic@df63d0f427

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>
[m2450] Add CMake source groups to target 'game'

This is the exact same grouping as it is currently in the VC 2012 files.
These groupings will have to be refactored at some point as they are not
very logical.

Based on cmangos/mangos-classic@fa7b2746a7

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>
[m2451] CMake: generic way to build a script library

Added new parameter INCLUDE_BINDINGS_DIR which can be set to the name of a
folder inside src/bindings/.

Includes the script library in src/bindings/ with the defined name.
The name must correspond to the name of the folder and the folder must contain
a valid CMakeLists.txt

Note: if you currently use a script library, you will probably get a merge
problem on src/bindings/CMakeLists.txt as you will have modified this file
manually. Please use the new version of this file and rerun CMake once with the
parameter -DINCLUDE_BINDINGS_DIR=ScriptDev2 (if you are not using SD2 but
another script library, replace ScriptDev2 with the name of the folder in
src/bindings/).

If you do not use a script library you should not have any merge problems
and you don't need to do anything.

Based on cmangos/mangos-classic@a9a6148bf5

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>