Docs: Added quotes for uniformity

Closes gh-801
New Rule: requireLineBreakAfterVariableAssignment

Fixes #540
Closes gh-780
New rules: (require | disallow)SpaceBetweenArguments

* requireSpaceBetweenArguments: validates that call expression arguments have
  the correct spacing before and after.

* disallowSpaceBetweenArguments: validates that call expression arguments have
  no space after the separator token

Fixes #771
Closes gh-774