Add support for Express 4

Express 3 and below are no longer supported
Version bumped to 1.1.0

Based on code by AdamBInfinity https://github.com/jsantell/poet/commit/05e48f43c8db277c03a1dc97ee7e52ec04818a4d
Merge pull request #102 from alexbirkett/express_4_support

Add support for Express 4