Updated basically everything ...

The following improvements have been made:
- rewrote the GF256-Math with lookup-tables -> everything is now ~5x faster!
- all classes and methods are now documented
- implemented "Unconditionally Secure Robust Secret Sharing with Compact Shares (USRSSwCompactShares)"
- added additional secure and also faster random-number-generators (CTRPRNG, StreamPRNG, SHA1PRNG; some of them based on the bouncycastle-API)
- reconstruction algorithms are now exchangeable (ErasureDecoder, BerlekampWelch-Decoder)
- cleaned up code and removed redundancies with new helper-classes
- expanded unit-tests
- resolved some tickets (see below)
- added some TODOs for  newly discovered problems

In addition the following issues have been resolved:
    - ShareSerializer now support shares of all types
    - Share has been changed to support multiple types (for example Rabin-Ben-Or needs to be RABIN_BEN_OR, KRAWCZYK, REED_SOLOMON and SHAMIR at the same time!)
    - added unit-tests
    - implemented basic Berlekamp-Welch-Decoder (reconstruction algorithms are now exchangeable)
    - added unit-tests

(I kind of forgot to do intermediate commits ...)