Refactor accessors so that all magic occurs in the project call. Close #699.

Accessors now have a pointer to their Plot, which allows them to dynamically
grab the right metadata.
[minor] Adjust JSDoc formatting + variable naming per @bmalehorn's suggestions
Merge branch 'master' into accessor-refactor

Conflicts:
	plottable.d.ts
	plottable.js
	src/core/dataSource.ts
	src/utils/utils.ts
Update built files
Merge branch 'master' into accessor-refactor

Conflicts:
	plottable.js
	src/core/dataSource.ts
Merge pull request #726 from palantir/accessor-refactor

Refactor accessors so that all magic occurs in the project call. Close #...