Add barcodeScanner setting to Site

Also clean up a few functions since I was in the neighborhood.
Barcode Scanner: Add icon resources
Add 'Scan QR Code' as top level action

The data from the QR code is then parsed as a URL and the appropriate
guide is opened in GuideViewActivity.
Use reflection to open barcode scanner

Otherwise the code doesn't compile for apps hat don't have the barcode
scanner because the dependency isn't specified.
Fix barcode scanner flavor dependencies

You must specify "{flavor}Compile" to compile it only for that flavor.
Otherwise it will be included for all flavors.
Use reflection for barcode result parsing

Now the code can handle the missing dependency.
Merge branch 'master' into barcode-scanner
Robustify guide view by URL

Now it gracefully handles invalid guide URLs and only switches to a
different site if it is the dozuki app.
Merge branch 'master' into barcode-scanner
Clean up menu code

We aren't at all consistent with calling super or returning the correct
value in the options methods e.g. onOptionsItemSelected. This makes it
consistent with the examples in the Android docs.
Add menu item for barcode scanner
Add CheatSheet to custom menu item
Display a toast on barcode failures

It shouldn't ever happen but in case it does it's nice to tell the user that something
went wrong rather than silently failing.
Change QR code icon

Also remove the old ones since we aren't going to use them.
Put search in between site list and scan barcode
Change "Scan QR Code" to "Scan" in menu

"Scan QR Code" is rather long for a menu item so it is now shortened to
"Scan". The navigation drawer still uses "Scan QR Code".
Merge remote-tracking branch 'origin/master' into clean-up-menu-items
Merge pull request #156 from iFixit/clean-up-menu-items

Clean up menu code
Merge remote-tracking branch 'origin/master' into barcode-scanner

Conflicts:
	App/res/menu/search_menu.xml
	App/src/com/dozuki/ifixit/ui/BaseSearchMenuDrawerActivity.java
Disable barcode scanning for now

The feature is done but we don't want to release it quite yet. This
disables it for now but can be easily enabled.