Rename 'web development' to 'front end development'

As pointed out in https://github.com/sindresorhus/awesome/commit/628177031145786bc4829b3db2e307612f0d7c37, the naming of this section isn't really correct. This fits better.
@sindresorhus I see this written in both ways all over the place. http://en.wiktionary.org/wiki/front_end#Noun

If you like `Front-end` more, I'il just update it ;)