HiC.scala
    Fixed but in HiC.buildInteractionGraph.  nregions was updated with
    by calculating math.ceil(length/resolution).toInt.  But since length
    and resolution are both Ints, length/resolution would return an Int
    thereby not yielding the desired result.  So changed it to
    math.ceil(length.toDouble/resolution).toInt.

HiCTests.scala
    Added printMatrix test on test3.sam file to test for interactions
    between different chromosomes.

new file:   testdata/test3.sam