Add a Makefile rule to make it easy to update the npm deps (for jsx, jshint)
Add a Makefile rule to make it easy to update the npm deps (for jsx, jshint)

Test Plan:
Ran
   make
and saw it run 'npm install'

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D4036

Khan/khan-linter,Khan/khan-linter,Khan/khan-linter,Khan/khan-linter