EMI/GRIM: Nothing should be visible if actor is not in current set

When fiddling with the controls in the Palace of Prosthetics Guybrush is
temporarily put into set "nil". No items should be visible to him in this
situation.
EMI: Separate radius and center for mesh collision sphere
EMI: Flip y coordinate when creating screenshot textures

The MakeScreenTextures() opcode is used to create texture tiles from the
current screen content for use with an overworld actor, e.g. when fading over
the slides in the intro. With OpenGL the created textures were mirrorered in
y direction because OpenGL uses a different coordinate system where (0, 0)
is the bottom left corner.
EMI: Fix various movies

- several movies (e.g. at the boulder puzzle on vista point)
  were not played

- enhance search for BINK header (some movie files don't have a
  SMUSH header and for others the movies starts at a higher position in
  the stream)
Merge pull request #792 from chkr-private/movie-fixes

EMI: Fix movies for boulder puzzle on vista point
EMI: Fix rotation of overworld actors
Merge remote-tracking branch 'inguin/emi-freeze-frame'
Merge remote-tracking branch 'inguin/emi-fixes'
Merge remote-tracking branch 'inguin/emi-overworld'
EMI: fix pause handling

On vista point it may happen that two sequences for the rock landings
are executed at the same time. Although they intend to be locked via
pause_scripts(), changing the set will call unpause_scripts() and unlock
all of them.

The patch will use the optional parameter for (un)pause_scripts() to
determine whether the pause calls should be counting (e.g. when
switching a set or opening the inventory) or not.
Merge pull request #793 from chkr-private/pause-handling

EMI: fix pause handling
EMI: Mangle filename when searching for shared material
EMI: Store materials in costume, not in mesh

When multiple meshes in an EMI costume use the same material each will have
its own Grim::Material instance. If a material used by multiple meshes is
changed by a texi chore the instances will become inconsistent.

With this patch materials are managed by the costume, and there will only
be one instance of each reference material.
EMI: Store active texture index for materials
Merge pull request #798 from inguin/emi-materials

EMI: Refactor handling of materials, fix texture animations
GRIM: Fix the stuffit include to be relitive to the project
GRIM: Fix misplaced override specifier in costumeemi.cpp
Merge pull request #803 from tombsar/master

GRIM: Syntax error when compiling with C++11 enabled
EMI: Ignore Actor:walkTo() if destination is unreachable

The path to the Curch of LeChuck has bogus coordinates as out point, so
the game will walk Guybrush to an invalid position when entering that
set. This patch will detect when no path can be found to the destination
position and ignore the walkTo() request in that case.

The behavior for Grim is unchanged in order to avoid the risk of breaking
the game. If the warning is never triggered the distinction can be removed.
EMI: invalidate sortorder after detaching actors

- the order of the active actors is based on the effective sort order
  which is based on the sortorder of actors itself but also on the
  attached actors
- invalidate the sortorder also when detaching actors
- this fixes two glitches in the final end scene (guybrush is still
  displayed after falling from the cliff and monkey robot is drawn in
  the foreground)