Changed custom email pattern matching regex to android.util.Patterns.EMAIL_ADDRESS to accommodate valid email addresses the original pattern did not. (e.g. a@aaa.aa, a+aaa@aaa.aaa) This commit is to fix issue 17 (https://github.com/WhisperSystems/TextSecure/issues/17)
The best-effort memory cleaning logic for MasterSecrets
is no longer accurate, since they are being passed through
both Binder calls as well as Intents, blurring whether an
activity is using a MasterSecret which is a reference to
shared memory in the KeyCachingService or not.
The 1.X Android versions don't have the 2.X VERSION_CODE
symbols, so comparing against them in order to make 1.6
choices will throw runtime exceptions.