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)
Merge pull request #804 from chkr-private/sortorder-fixes

EMI: invalidate sortorder after changing attached actors
Merge pull request #794 from inguin/emi-walkto

GRIM/EMI: Ignore Actor:walkTo() if destination is unreachable
EMI: Reset sort order when changing sets

Some sets (e.g. the big monkey's engine room) set Guybrush's sort order
to a large value, causing him to become invisible in other places. This
patch resets the sort order for all actors when switching to a new set.
Merge pull request #801 from inguin/emi-sort-order

EMI: Reset sort order when changing sets
ALL: update year headers
BUILD: Enable JPEG detection for Myst3.
VIDEO: Fix Bink seeking after video decoder API change
MYST3: Add JPEG as a dependency
EMI: use enableSubtitles parameter of StartMovie lua function