Move 'use strict' to file scope

Right now JSHint is throwing errors on the globals being used in the
functions. The workaround for this bug is to throw our globals in the
.jshintrc and set /*global someGlobal:true*/ when defining someGlobal
but I opened jshint/jshint#1665 to deal with this bug.
Merge pull request #143 from christianbundy/new-branch

Move 'use strict' to file scope