Multiple evaluation of tests and implementations

-- Added a "--all" option to run all implementations of the PairHMM sequentially
-- Added the option to run multiple PairHMM implementations sequentially (by using "--caching --logless" for example to run both these implementations)
-- Added the option of running multiple test sets against all the requested PairHMM implementation. Test sets are entered in the command line.
Added ABS to the precision calculation