Ship Visual Studio 10 runtime DLLs with Tiled

They're not available on all Windows systems.

Closes #542
Fixed linker error on Mac OS X when compiling with Qt 5

Based on Qt Creator commit a4e593c910cca.
Rename tile selection functions in map document.

setTileSelection is now setSelectedArea
tileSelection is now selectedArea
tileSelectionChanged is now selectedAreaChanged
Renamed undo command ChangeTileSelection to ChangeSelectedArea.
Renamed changetileselection.h/cpp to changeselectedarea.h/cpp
Fixed issue with zoom combo box jumping to 1%

Was broken by c6bc0a1e4061cf788342b120e8abcad43064c929. Thanks to
@obeea for finding this.

Fixes #665
Merge pull request #666 from despondentdonkey/refactor

Rename tile selection functions and undo command.