remove WA measuring of sequence character stuff in genomeview, and limiting of the max zoom to the size of sequence characters.  Reverts 4ba3f7db27e66e46d91addab0bbb3e7ebb20fc79, 9e3270d817b7f08d5d5605d60e5249da19a8c2a5, 4027d7f5cb0badff527edce001cdd83361574c0c
fix bug in HTMLFeatures subfeature centering that was exposed at higher zoom levels on BAM tracks