Add HexLength, HexNotation and HexValidation

Change-Id: I78417a2617f901ad40393f0b27f0ff06c251a8d9
Reviewed-on: http://gerrit.causes.com/37972
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>
Cleanup Hex{Length,Notation,Validation}

Some minor style and grammar tweaks.

Change-Id: Ida177179a563f3d62dafb234accaccf38879c370
Reviewed-on: http://gerrit.causes.com/37973
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>