Optimize seq.scala a bit.
Optimize seq.scala a bit.

Try to minimize conditional checks inside of loops. The new strategy
will be especially good in the case where one sequence is significantly
longer than the other. But even in the general case there should be
fewer conditional tests now.

siddhartha-gadgil/spire,AlecZorab/spire,guersam/spire,non/spire,kevinmeredith/spire,codeaudit/spire,rklaehn/spire,woparry/spire,tixxit/spire,tixxit/spire,AlecZorab/spire,rklaehn/spire,JackSullivan/spire,woparry/spire,adampingel/spire,non/spire,siddhartha-gadgil/spire,kevinmeredith/spire,JackSullivan/spire,guersam/spire,codeaudit/spire,adampingel/spire