Added support for do statement bodies that are not block statements, in the same way that we can already do with e.g. if or while statements.

The new functionality will obey the `curly` option and allows the statement body to appear on the same line or the following line (in which case existing indentation rules will apply)
Merge pull request #1062 from jamesallardice/non-curly-do

Add support for `do` statement bodies that are not block statements