Couple utilities, bed12->picard interval converter

[roryk]

Pared down the unit test data so it is small as well.

[chapmanb]

Awesome, thanks Rory. The only change I made was to remove the dependency on the samtools executable and use pysam instead. I already have a brutal number of BAM manipulation dependencies with Picard and pysam so am trying to avoid using samtools unless it's explicitly needed (like for variant calling).