There is nothing built-in to the editor, and there is no tool (currently), but that would be a very helpful tool to create...

Even Eclipse hasn't something like that built in. Perhaps because programmers want to control what is saved...
Typing Ctrl+S (or equivalent on Mac) regularly is an old habit, working in all editors I know.

i think it would be reasonable to have back-ups though. For me they're sorely missed in a lot of applications.

For a coder, backup is named VCS, version control system (also named SCM: source code management).
I recommend DVCS, the distributed version, more modern, like Bazaar (my personal choice), Mercurial or Git.
I find CVS and SVN outdated, heavy and clumsy.