implemented CevallosUSRSS

also had to modify some other files to make them compatible with the new
SecretSharing scheme
Adjusted the gitignore files to ignore eclipse and OS X meta files.
Fixed a boundary check bug.
Saved a little bit memory.
Changed the elimination round algorithm from O(n^3) to O(n^2)
Merge pull request #15 from gye-tgm/cevallos

add Cevallos. There are some missing cleanups, but those should be done in the near future..