Exceptions and onFailure Messages

• Fixed ProviderException that was uncaught and causing crashes in several devices (Issue#12)
• Messages were printed to stacktrace when async methods are called, now they are delivered to onFailure() methods.

Async Errors and Static Methods

• Need to call init() once for context dependency.
• Change all the methods to static.
• Errors from Async calls were not reported, they are now passed in onFailure methods.
• Generate random phrase now accepts parameter to specify length of phrase.