Source formatting.
Fixing tests, removing big files.

Couple of fixes here:
1. fixed the gene assembly itself, which was failing when there were no
CDS features reported (and was also failing to join correctly on the
gene feature IDs themselves).
2. Moved the two 'ignore' tests back into operation.
3. Changed the test files themselves, so we no longer depend on the set
of gene annotations from chr20 (which was 16M) and that file can be
deleted.