Make a rule on blocks and not only on lines

* There is now a ```matchblock``` function available in each rule.
* In the ```matchblock```, you have access to the filepath
  and the type of the file (playbooks, tasks, handlers, meta, ...).
* An example is provided to check that all tasks and handlers have a tag.
The line match function now takes the file data in argument too
Add a function to get the rolename from a filepath
Added missing whitespace back to README.md