Make the horizontal positioning of custom text better looking in ex_font_multiline
Fixed TRIGGER_HAPPY buttons for Linux joystick.
Added Windows haptics driver, XInput joystick driver. (Beoran)
Demand load xinput dll
Fix warnings in wjoyxi.c

Those two functions weren't exported, so they can be static.
Silence a redefinition warning under MinGW-w64
Change all direct accesses to ALLEGRO_BITMAP::format to al_get_bitmap_format.

In many cases this isn't actually necessary (as we are guaranteed to be dealing
with parent bitmaps) but:

1. Not using al_get_bitmap_format invites human error in case that function is
   refactored
2. It is a premature optimization
Change all direct accesses to ALLEGRO_BITMAP::flags to al_get_bitmap_flags.

See previous commit for the rationalle.
Simplify al_convert_bitmap

In particular, the sub-bitmaps are now not touched, and just the parent is
converted.
Update the documentation for al_convert_bitmap
Rename ALLEGRO_BITMAP::flags, format to _flags and _format.

This highlights their private nature and will raise obvious errors in case some
place still accesses them directly. The leading underscore just seemed like a
good convention.
Give the D3D backbuffer bitmap a valid flag