always declare O_BINARY

closes #461
Fix mouse issues on OS X (fix #458)

Now we generate she::Event::MouseEnter/Leave events correctly when the
mouse leaves or enters into the window to show the native cursor again
when necessary.

Close #466
Fix Alt+Mnemonic on Mac OS X
Don't add extra ASEPRITE block to .gif file because Photoshop cannot load them
Fix bug moving cels between layers

The image wasn't being copied correctly when the
source cel's (x,y) was != (0,0)
Add some DocRangeOps.MoveCels tests
Fix crash in SelectAccelerator::KeyField when a Unicode char is pressed

The problem is that Accelerator::toString() wasn't returning valid utf-8
strings for Unicode characters.
Merge branch '1.0'

* In this branch the Alt+mnemonic issues are solved in "she" layer when the
  she::Event is generated (see src/she/alleg4/key_poller.cpp)
* Mouse cursor issues on OS X are solved in src/she/alleg4/mouse_poller.cpp

Conflicts:
	src/app/test_context.h
	src/ui/manager.cpp
Fix ReplaceInkProcessing to work correctly with transparent colors (fix #435)

Now we can replace a solid color with transparent in RGBA and Grayscale
images.
Fix compilation error in new document_api_tests.cpp test merged from d176839bf4652317f6fd01ec7dfe1cd1017b8e5f (close #515)
Fix underlinking with USE_SHARED_ALLEGRO4=ON
Merge pull request #497 from Mailaender/patch-2

Fix error: 'O_BINARY' was not declared in this scope (close #461)
Merge pull request #516 from hasufell/underlinking_fix

Link with platforms libs when USE_SHARED_ALLEGRO4=ON (fix #513, #514)
Fix problems with multiple editors in MovingPixelsState (fix #419)
Fix #392 - Crash when another monitor is plugged in

When we change the number of monitors, we've to restore the primary
DirectDraw surface, but it cannot be just "restored", it must be
re-created.

Note: probably the real fix for #436 too
Merge branch '1.0'

Conflicts:
	src/app/color_utils.cpp
	src/app/tools/ink_processing.h
Fix more OS X cursor issues

Fixed problems with a hidden mouse cursor when we activated Aseprite
window from other windows, or from the Mission Control, or with Cmd+Alt.
Remove unused variable
Add support to serialize special unicode chars in ui::Accelerator
Change the way ProgramOptions store specified args

Now we can parse command line arguments sequentially in the same order they
were specified.