Update Silica to 0.1.1
Add --deep to code signing to ensure that Sparkle gets codesigned.
Bump version for release 0.8.3.
Update README.md

Include update to 0.8.3.
Update README.md

Add a note about 10.9 and the last version supporting 10.8.
adding error handling for non existant layouts
Merge remote-tracking branch 'upstream/master' into layout-hotkey-support