Three changes:
1. Fix inconsistent "pwd" behavior by using make's $(CURDIR) builtin.
2. Change bash shebang to the more-portable form.
3. Tell users when Pelican and SimpleHTTPServer have been backgrounded.
This script and the small changes to quick start's makefile make for easily launching and killing of pelican --debug --autoreload and SimpleHTTPServer.
This is extra useful for working on templates.
