* Elminates a lot of logic in the AnsibleComposer class.
* Update tests with new column offsets.  The rule should now be
  consistently: Column is the start of the entry's value (so for
  strings, the first non-space after the entry beginning, for dicts, the
  first character of the first key)

* Changes AnsibleConstructor so that only unicode strings are returned
  (no str type)
* Tracks line, column numbers for strings
* Adds unittests for AnsibleLoader (generic for all the yaml parsing)