[Patch] Refactor regex executors

[Paolo Carlini]

On 10/25/2013 06:30 AM, Tim Shen wrote:
> This patch optimizes BFS executor by removing quantifier tracking, but
> precisely control the assignment order of the variable recording the
> optimal solution.
Ok. Are there measurable performance changes at this point? I'm asking 
because we should take the chance and add performance testcases when we 
improve the performance: later, unless somebody files a specific Bug 
report, we become lazy about those, I know that ;)

Paolo.