Create small reference for fusioncatcher (chr4)

[alanmmobbs93]

Create small reference files for fusion catcher. Target human chromosome 4, or look for another chr/combination.

Background: the current available reference (downloadable with the local module or from the official tool repository) is large and the tests take too long to complete.

CC: @nschcolnicov @atrigila @grst @apeltzer

[nschcolnicov]

Two approaches we discussed with @alanmmobbs93:
Proceed with extracting only chr4, but we will need to create all new indices for bowtie, etc.
Use a different species with a smaller genome for the tests

[apeltzer]

chr4 if I'm asked to throw my cent in ;-) Reason: The pipeline will be and is used on human data --> the closer we stay with the intended use, the better.