Add leading/trailing classes to hard tab tokens

Previously the leading-whitespace and trailing-whitespace classes
were never added to tokens that were hard tabs.
:lipstick: Put leading spec first
Add spec for all whitespace lines
Assert other whitespace class is not present
Merge pull request #3555 from atom/ks-include-leading-trailing-classes-for-hard-tabs

Add leading/trailing whitespace classes to hard tab tokens