Added ability to enforce strict task name argument matching

[tgiesselmann-ep]

Hi,

Sometimes the task name matching feature can be a dangerous thing and one might only want to allow exactly matching task names as arguments.

This merge request introduces the ability to add the statement __TASK_NAME_RESOLVER__ = 'strict' to the build file to tell pynt to only accept fully matching task names.

Unit tests have been updated.

Thanks, Torben