Yardoc for the DoubleEntry module

http://rubydoc.info/github/envato/double_entry/yardoc/frames

There's still more methods here to document. But let's get this work merged in, considering the team thinks it's a good start.
essentially: options:```
:scope => something that you can call id on (ie: user)

:from => created_at start date
:to => created_at end date

:at => created_at before or =to date (will take priority over from/to)

:code => a single code to scope the lines to
:codes => a set of codes to scope the lines to
```