Refactor tests with anonymous structs
Add support for storing comments with keys
Added support for setting and clearing comments.
Return keys in the order they are in the original input.
Add support for writing properties files with comments.
Allow comment to start directly after the prefix.
Added tests for Set()
Fixed bug in Set() which was not properly checking for circular references.
Added MustSet().
Migrated to gopkg.in/check.v1.
Merge branch 'comment_branch'