Sometimes calls to app.err.Fatalf would fail to print the error to the
console, and fail to show "A crash report has been saves to...". Both of
these should be fixed now.
The last 100 lines of logs are now cached, and when a crash occurs, they
are saved to a file in the temp directory ("/tmp" on *nix), and pretty
HTML version is also created and opened in the browser.
* Currently only handles panics, will be included in more places soon
* Copy button and button to generate a GH issue will be added