Merge pull request #33 from jonathanKingston/master

Making @throws have a conditional type fixes #31
Extract to skipToTag
Move option lineNumber setting to appropriate position.
Extract JSDoc tag parser code to TagParser (part 1)

To support declarative tag parsing.
Add Rules object to define parsing rules declaratively
Support @kind

ref: http://usejsdoc.org/tags-kind.html
Support @todo

http://usejsdoc.org/tags-todo.html
Support @summary

ref: http://usejsdoc.org/tags-summary.html
Support `@variation`
ref: http://usejsdoc.org/tags-variation.html