This adds a config option to the JSHint plugin, allowing admins to specify

which JSHint options should be turned on or off. The contents of a .jshintrc

file can simply be copied into this field.
I also fixed a small bug in make_tempfile() (the default value of None for

extension would cause an error since mkstemp()'s suffix must be a string).

Without any config specified, I published a review request, saw the worker run

jshint without the --config flag. The published review did not include issues

on unused variables.
Using the same config as reviewboard/static/rb/js/.jshintrc, I published a

review request, and saw the worker run jshint with the --config flag this time.

The published review included issues on unused variables.