DustMite updated

[Vladimir Panteleev]

I played with some algorithms today and got about a 7x 
improvement in reduction time for my test case. The data is now 
arranged into a binary tree, and the progress indicator was 
changed to reflect that. Let me know if I broke anything in the 
process.

No new features have been added. Still thinking about how to 
handle lists.

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DustMite is a tool which minimizes D source code.
https://github.com/CyberShadow/DustMite