Test case addition to make sure we don't keep on iterating executing the transaction when its been successful

Added SQL wildcard support to GeneAdaptor, TranscriptAdaptor and TranslationAdaptor -> fetch_all_by_external_name()
Actual modifications in DBEntryAdaptor. Features tested through gene.t

Subroutine added to optionally wrap values into arrays. Checks to see if the value is already an array and if so returns it untouched.

Updates for execute_into_hash() which now allows you to process a query which could return the same key multiple times and can support parameters being passed into the statement prepare() method.

Addition of utility classes for use in the Ensembl API. The first are shortcuts for asserting object/ref types and the second is a class which removes boilerplate from working with databases.