Adjust minor log message from signal changes

There was a log message stating that NodeAtlas had "caught SIGHUP",
despite the relevant signal having been changed to SIGUSR2. This commit
removes that text entirely, and leaves the remaining message: "Reloading
config".
Add /edit/ handler and improve edit.html.tmpl

The edit page is not yet ready, but this commit will make it prettier by
removing the unnecessary scripts, which were causing the section text to
float into the nav bar.

Ref #85
Merge branch 'development' of github.com:ProjectMeshnet/nodeatlas into development