CHANGED find method to restrict fetched columns
CHANGE Added varchar lengths to support mysql dialect
ADDED options to connect to a MySQL database
ADDED Docs
ADDED methods to get first/last exon of a gene
In the future this might be added as a binary column for each exon
CHANGED backwards compatibility
FIXED bug in .find()
Merge branch 'feature/exon-order' into develop
Merge branch 'feature/mysql_support' into develop