Heuristic added that greatly improves performance.

On the first pass through the theorems, only bound theorem expressions
that have at least one symbol in the goal (or a goal subexpression) are
inserted into the VC.

Also added a time to quit parameter to the applyTo method in the Theorem
class.
Removed java 8 dependencies.

Now compliant with java 7.
Merge pull request #121 from mikekab/TheoremBridging

Heuristic added that greatly improves performance.
Added prioritization module.

Improves performance by adding instantiated theorems in order of
relevance.
Improved heuristics.

Deeper proofs are now able to be completed; i.e.
Queue_Template.Selection_Sort_Realization.rb
Removed stray print
Merge pull request #123 from mikekab/TheoremBridging

Improved heuristics