external link styling jquery targets id but pages use class

[jhnc]

js/custom.js contains projectlight.markExternalLinks() which selects using #content but pages generated by drupal do not seem to contain a #content id but may contain several .content areas.

Because of this inconsistency, projectlight.markExternalLinks() never selects anything.

[thewilkybarkid]

It hasn't been used due to cambridgeuniversity/Project-Light#31, when resolved it can be added.