Fix for pages being repeated when running on Android Honeycomb.

Fixes bug #695191 - Mupdf Build49/armv7a & Android 3.1: cycles
through subset of pages & page scrubber

The problem here was that in Honeycomb, various bitmap operations
(including drawing via JNI) do not update the bitmap generation count.
When hardware acceleration is enabled, this means that the underlying GL
layer is not aware that the bitmap has changed, and ends up reusing old
textures.

To workaround this, we erase the bitmap before drawing the page. Erase
appears to be the only operation I could find (after pouring through the
source), which actually increments the generation count. The other option
would have been to disable hardware acceleration, but that was far less ideal.
Fix various Xcode analyzer warnings.

Most were pretty harmless, and were addressed by renaming functions to match the Core
Foundation naming conventions, but there was one actual memory leak, and some potential
uses of uninitialised data.
Add missing 'period' to files launched via 'Open In' before file extension.

Fixes bug #694711. As far as I could see, opening an XPS worked fine, the
first time. However, if the same file was opened a second time, then it
should have been saved with a number, e.g. foo(1).xps. However, the period
was ommitted, so the file wasn't recognised as an XPS.

This presumably wasn't an issue for PDF files, as PDF format is assumed
by default (I am guessing).
Fix deleting wrong file or crashing app if first file deleted.

Correct an off-by-one error in the file deletion code.