Minor tweak to link lua/luajit tool without Urho3D dependency libs.

These changes should also reduce prerequisite for building 32-bit luaJIT VM (for Android and RASPI) on 64-bit host/build system.
Added drag and tooltip to sample#2 HelloGUI
Fix various order of exposition to lua
For Travis CI - attempt to setup 32-bit and Android CI build.
For Travis CI - another attempt to add more CI build matrix.
For Travis CI - change the sh option from -e to -c.
For Travis CI - complete the last branching with a true command.
For Travis CI - subshell could not export var, so define it elsewhere.
For Travis CI - change the subshell to bash shell. Pardon our dust.
For Travis CI - temporary disable 32-bit. Android CI build is OK now!
Added Pool for WorkItem SharedPtrs to save allocation every frame. Its an optional construct to allow the user to create their own pools or not use the pool if they so desire.

Below is the profiling for the Octree and View changes to pooled allocation.

Before:
UpdateDrawables                        35    0.139    0.193    0.135     4.871
SortAndUpdateGeometry          35    0.080    0.135    0.077     2.802

After:
UpdateDrawables                        21    0.082    0.172    0.078     1.735
SortAndUpdateGeometry          21    0.054    0.069    0.052     1.144
Modify tolua_isnumber and tolua_isstring function to fixed issue #182.
Merge branch 'master' of https://github.com/urho3d/Urho3D
Fixed typo.
Use CMake path instead of native path. Closes #188.
Merge remote-tracking branch 'remotes/alexparlett/feature/pooled-work-queue'
Merge remote-tracking branch 'remotes/mike3d/master'
Minor code reorganization of the HelloGUI example. Removed SubscribeToEvents() as it was only used for 1 event and events were also subscribed to elsewhere.
Travis CI: API documentation update at 2014-02-11 20:02:28 UTC.
[ci skip]
Fix luajit runtime error on 64-bit Mac OS X build. [ci skip]