Fix multi cron

[rsromanowski]

Context

Setting up multiple cron jobs would allow both to run, but you could only reference the first one declared. The reason for this is subsequent calls to app.state('cron'...) (which occur in .use(cron(...)) would not overwrite cron in the app

• See commit af83c2c for reproducing tests

Changes

• Upgrade to elysia 0.7.0 to get access to remap functionality
• Update cron method to use remap instead of setting state directly

[rsromanowski]

Fixes #3