Implement Beast

BEAST: http://beast.bio.ed.ac.uk/Main_Page

We need BEAST to execute xml files in Galaxy. We should be able to see the log file and trees file while the program is running. This is very similar to Trinity. Also, when the program is finished running, it would be useful to know where the trees and log files are on knot (their path). Furthermore, BEAST makes use of multiple CPUs and/or GPUs. It would be very useful to have the option of running BEAST on CPUs vs GPUs.