fixed mixed indentation types and other whitespace clean up
tests of getting transcript by stable_id were broken

[FIXED] did not correctly reference the human genome instance
Transcript.Gene property now has correct attributes, fixed #23

[FIXED] rather than duplicate code for constructing Gene instances on the
     Transcript class, better to use an existing (and tested) method on the
     Genome class.
[CHANGED] explicitly reference result field from returned db query