Develop

Code for flexible entry point detection.

* Added  EntryPointDetector API
  * Added SignatureEntryPointDetector
  * Added MethodNameEntrypointDetector
  * Added SubSignatureEntryPointDetector
  * Added MainDetector
  * Added ConcreteMethodDetector
* Updated EntryPoints, Scene, OptionsBase
* Tested on Clara (some time ago) - got the same number of successes and failures as vanilla soot