tests for renaming root in Match/Selector
Merge pull request #124 from mossprescott/selector-rename-tests

tests for renaming root in Match/Selector
update tests to use DocField.apply
Nicer toStrings for physical plan (Fixes #125)
fix tests so failures report the right line number
Merge pull request #126 from mossprescott/minor

fix tests so failures report the right line number
emit ADT constructors for selectors in RenderTree
Now that we have a separate mechanism to get the JavaScript form, this seems more useful
prefix ExprOp toStrings
prettify Sort toString
prefix Selector toStrings
Merge pull request #127 from mossprescott/wip/125

Nicer toStrings for physical plan
Tests for order by with nested fields (Fixes #53)
implementation not changed, tests did not turn up any problems
fix parsing of ">="
Merge pull request #129 from mossprescott/minor

fix parsing of ">="
test for nested projection in order by
Merge pull request #128 from mossprescott/wip/53

Tests for order by with nested fields (Fixes #53)
refactor MongoDBEvaluator to make the logic reusable
use MongoDBEvaluator to convert physical plan to JS (Fixes #111)
Merge pull request #136 from mossprescott/issue111a

New PR, on a new branch, still fixing #111
capture result of each (major) phase including result tree in a PhaseResult ADT