Keep track of TextEditor focus in Alert transitions.

When transitioning from a Canvas Screen to an Alert Screen, keep track
of which TextEditor has focus. When returning to the Canvas Screen,
focus the TextEditor. This helps us match app expectations with regard
to keyboard visibility.
Merge branch 'master' of https://github.com/TimAbraldes/j2me.js into keyboard
Download JAD manifest and JAR archive at first run; store it in the FS for subsequent runs
Add tests for JAD/JAR downloading
Fix manifest parsing with entries that have ':' character in the value
Use systemXHR to circumvent CORS
Fix typo in main.js
Revert "Keep track of TextEditor focus in Alert transitions."

This reverts commit 5bee769f28e11cea283b2e1e216a7a6c6c05d6c0.
Keep track of TextEditor focus in Alert transitions.

When transitioning from a Canvas Screen to an Alert Screen, keep track
of which TextEditor has focus. When returning to the Canvas Screen,
focus the TextEditor. This helps us match app expectations with regard
to keyboard visibility.

This patch also adds plumbing to allow RunTests tests to change the
current Displayable and compare the pixels of the current screen to a
reference image. These changes allow us to convert a bunch of gfx tests
to RunTests tests. The first converted test is AlertTest, which has been
updated to also test that focus is being tracked properly across showing
Alerts.
Merge branch 'master' of https://github.com/TimAbraldes/j2me.js into keyboard
Use TestHarness.setScreenAndWait from TestAlert
Add newline at the end of the file
Cleanup object URLs in gfx.js

Fix for issue #694.
- Always convert images to canvases
- Cleanup object URL after conversion
Remove convertNativeImageData
Merge branch 'master' of https://github.com/TimAbraldes/j2me.js into keyboard

Conflicts:
	tests/automation.js
	tests/native.js
Merge branch 'master' into obj_url_leak_1
Merge pull request #705 from EricRahm/obj_url_leak_1

Cleanup object URLs in gfx.js
Merge branch 'master' of https://github.com/andreasgal/j2me.js into download_jad

Conflicts:
	index.js
	manifest.webapp
Merge pull request #695 from marco-c/download_jad

Download JAR on first run given an URL to a JAD manifest
Cleanup object URLs in localmsg

Fix for issue #708

- Add image cleanup function
- _sendBackScaledImage cleans up
- onerror cleans up