added some more documentation to RandomSource (+ deleted JavaRandomSource)
added SHA1-PRNG
added CTR-PRNG
added Stream-PRNG and bouncy-castle dependency to pom.xml
added a simple unit-test for performance comparison of the different PRNGs
fixed code formatting
now throwing Impossible-Exceptions

Code is now throwing Impossible-Exceptions in catch-blocks that should
actually never be entered. (just to be safe)
Merge pull request #7 from efrantar-tgm/random

Added new PRNGs