Remove code to prevent router reloading in dev.

This env var switch was used so that it wasn't necessary to have the
router running in dev mode.  Remove this now that we're going to be
running the router on the dev VM.
Add option to swallow router reload connection errors

This is set in development mode so that this will reload the router if
it's running, but not fail if it's not running.
Don't attempt to reload routes from seeds on CI.

The router won't be running on the CI machine, and as it's runnning with
Rails.env test, the default initializer doesn't catch this.
Merge pull request #49 from alphagov/enable_router_reloading_in_dev

Enable router reloading in dev