changes the logging_handler to raise exceptions

this enables us to log and then raise exceptions.
Adds Execute Folders

Adding a method that wraps and executes the `execute_folder` method,
when passed an array of “folders,” for each entry in the array.

This method differs from the style of `execute_folder` and `execute` by
including basic exception handling.

No existing functionality is altered by the addition of this method.
Merge pull request #6 from blankenshipz/adds_execute_folders

Adds Execute Folders
Merge branch 'changes_threequel_to_throw_exceptions' of github.com:blankenshipz/threequel into blankenshipz-changes_threequel_to_throw_exceptions

* 'changes_threequel_to_throw_exceptions' of github.com:blankenshipz/threequel:
  changes the logging_handler to raise exceptions

Conflicts:
	lib/threequel/logging_handler.rb
t push origin masterMerge branch 'blankenshipz-changes_threequel_to_throw_exceptions'

* blankenshipz-changes_threequel_to_throw_exceptions:
  changes the logging_handler to raise exceptions