Added .ropeproject exception to gitignore.
validators/title: removed obsolete method.

The method `required_facters` of the Validador TitleValidator is not
being used in the project. So I removed it.
Added heading hierarchy validators.
Fixed misspelling on name of method.
Fixing heading hierarchy description string.
Refactoring the way to update pages score
Cosmetic changes
Updating waffle badge
Renamed `semantic` fact category to `semantics`.
Testing violation definitions of heading hierarchy

The heading hierarchy validator are now 100% covered of tests.
Page model: Duplicate entry is not 'error'
Releasing 0.10.0
Added image alt too big validator

The `ImageWithoutAltAttributeValidator` was refactored and renamed to
a more gereric Validator to support a new kind of violation called
`invalid.images.alt_too_big`.