Add PyCharm folder to .gitignore
Apply eco-benefits template server-side instead of client-side
DRY out search_tree_benefits()
Add tests for search_tree_benefits
Format eco-benefits more usefully

* Add label on each benefit (yet to be internationalized)
* Add unit on each benefit (yet to be locale-sensitive)
* Add number format string on each benefit
* Simplify template to use a loop
Rewrite SearchTreeBenefitsTests

Rather than testing returned eco-benefits values, test that:
* trees without diameter, species, or itree code are ignored for benefits calculations
* extrapolated benefits are larger than non-extrapolated benefits

Also, simplify extrapolation calculation and reformat its code a bit
Merge pull request #92 from RickMohr/ecobenefits-server-template

Ecobenefits server template