Converts region mapping to genomic mapping

This takes a BAM file that has been mapped to a genomic region and converts
the mapping to genomic coordinates.  This can be used to convert reads mapped
against a junction library or targeted resequencing back to genomic
coordinates.  The names of the reference sequences should be named:
chrom:start-end (0-based start).  If there are gaps (junctions), they should
be named: chrom:start-end,start-end,etc...

In this is the case, this script will ensure the proper conversion of
reference, start position, and CIGAR alignment.

Example 1:
chr1:1000-2000    20    50M

converted to:
chr1    1020    50M

Example 2:
chr1:1000-1050,2000-2050,3000-4000    25    100M

converted to:
chr1    1025    25M950N50M950M25M



Usage: bamutils convertregion {-overlap} in.bam out.bam [chrom.sizes]

(Note: A samtools faidx file can be used for the chrom.sizes file.)

Options:
  -f             Force overwriting an existing out.bam file
  -unmapped      Keep all unmapped reads in the output file (including invalid junction reads)

  -overlap N     Require that all reads must overlap a splice junction
                 by N bases. This also removes unmapped reads. [default 4]
                 Set to zero to allow all reads.

  -validateonly  Don't convert the reference and position, just confirm that
                 the reads correctly overlap a junction. Any reads that don't
                 overlap a junction will not be written to the out.bam file.

                 If -validateonly is set, then the chrom.sizes file isn't
                 required.