Consequence type gbpa

- Added classes Hgvs & RefseAccession
- Added transformToEnsemblFormat to Variant class
- Added Groovy Spock tests  HgvsTest y RefseeAccesionTest. Added dependencies to pom.xml and maven plugin to compile groovy files, so spock tests could run "out of the box".
- Added test resources: testReferenceSequence fasta and fai
- Added VariantTransformToEnsemblFormatTest test