Using the XPM format for images has become a maintenance problem because
people don't know how to create them. This commit removes all XPM images
and all C files that contain PNG images. DolphinWX now uses the PNGs
in the Resources folder instead, just like DolphinQt and DolphinQt2 do.
Minor other alterations that relate to above as well.
Also added the PanicAlertT version of alerts for some error messages that
use PanicAlert. We want the user to actually understand why the error
occurred.
Breakpoints have one, but memchecks don't, despite being cleared directly in the breakpoint window.
Now DolphinWX should call the interface functions and not the direct functions of the breakpoints or memchecks for clearing.
