Created new (range) validator

Signed-off-by: Exikle <dixondcunha@hotmail.com>
changed the way the contxt is obtained

Signed-off-by: Exikle <dixondcunha@hotmail.com>
Signed-off-by: Exikle <dixondcunha@hotmail.com>
Merge pull request #33 from Exikle/master

RangeValidator