Add dotPsci task to gulpfile

If you return the stream Gulp will wait for that task to be complete before moving on to the others in a list of tasks. This allows for tasks to have dependencies. For speed sake, if a task is independent then its best to let it be async.

I just noticed that it might be better to use gulp.src([paths.src].concat(paths.bowerSrc)) instead of just the bowerSrc does that seem right? I'm just learning PureScript.