Add weighting parameter to admin panel

[cjmyers]

Add ability to change the weights to the final score. Namely tradeoff between PageRank and Keyword score, and the cluster devalue score.

[cjmyers]

Note that that this is what causes unexpected results like BBa_B0030 returning BBa_B0034 as the top hit. It also allows for BBa_F2260 to return BBa_F2620 as top hit reflecting a typo.