Rmats2sashimiplot

* Rename -t parameter to --event-type
* Add --keep-event-chr-prefix and --remove-event-chr-prefix
* Allow s1,s2,b1,b2 arguments to be a file containing paths
* Add --fig-height and --fig-width
* Replace deprecated matplotlib import
* Allow using a csi index for bam files
* Fix exon coordinate display for events
* Only require a label argument if the sample group is provided
* Fix for --min-counts parameter
* Reduce empty space in plot
* Replace ':' with '_' to support more file systems

* Support Python 3
* Allow running a single sample
* Handle mRNA and transcript the same in the annotation files
* Handle BAMs without the chr prefix from the rmats events file

- The BAM files should follow the same headers naming convention as the GFF file. Please check the sequence name in BAM and GFF before running rmats2sashimiplot.

Changed the default minimum junction count (--min-counts) to 0.

- Preliminary release of rmats2sashimiplot.
- Highly customizable.
- Bug fix for y-axis definition. (Using a modified RPKM now.)
- Bug fix for A3SS and A5SS.