Added a more specific GTF parser which can identify subclasses of
features using the Ensembl notation.  It works, but is using too much
memory at the moment which we need to sort out.  I haven't yet put in
the code to pass across the coding exons to the appropriate CDS features
so this also needs to be done.

Have extended the feature class to allow for a sub-type annotation, but
we'll also need to extend the FeatureType class to recognise this
distinction.
Found the reason for the really poor memory usage - was reading the
wrong field for the subclass.

The feature class is now extended to show all of the biotypes, and the
coverage plot also now uses all of these, but there are now too many to
be sensible.  I think we'll need to think about which ones we want to
keep, which we throw away and which we might want to merge.  Not sure
there's going to be an easy answer to this.
Merge branch 'master' of https://github.com/s-andrews/BamQC.git

Conflicts:
	uk/ac/babraham/BamQC/Modules/ModuleFactory.java