export hardcoded string to strings.xml
add an errorType and an errorMessage to all onFailure callbacks
fix calls to ApiHelper tasks
add a toast error message when media upload fails
Merge branch 'develop' into issue/218-upload-task-error

Fix Conflicts in:
	src/org/xmlrpc/android/ApiHelper.java
Log all setError from ApiHelper
track Throwable instead of Exception
add Throwable to onFailure
update ApiHelper.GenericCallBack receivers
fix unhandled JSON exception
Fix an errorType check
Merge pull request #639 from wordpress-mobile/issue/218-upload-task-error

Fix #218: upload task error