Fixed using index with OrderBy. Fixes #35
Added multi indexes. Fixes #36
Added some more tests and fixed not being able to evaluate nil
Fixed expr not working properly. Fixes #28
Fixed Expr not supporting arrays, fixes #39
Removed test
Updated description of OrderBy
Merge pull request #40 from AgFlow/master

Updated description of OrderBy
Added some documentation regarding encoding+decoding of structs based off of the encoding/json docs
Add test to show issue #43
Return a nil ResultRow for an empty RunRow

Fixes #43
Merge pull request #46 from baruch/issue-43

Fix issue 43 (RunRow returns error instead of a nil ResultRow)
Merge remote-tracking branch 'upstream/master'