formatting
src/spartan/utils/annotations/ensembl/gff3.py:

- class SimpleFeatureGFF3(intervals.SimpleFeature):
	* added self.children / self.parents
fixed intervals.SimpleFeature.__init__() to play nice with
gff3.GFF3.__init__()
src/spartan/utils/spreadsheets.py:

Helper functions to open and manipulate excel-type spreadsheets.