[Bf-committers] Please turn off Auto Run Python Scripts by default

[Campbell Barton]

Update on whats going on:

- Default has been changed not to auto-run scripts, with option to
reload a blend if it attempts to run a script.
looks like this: http://www.graphicall.org/ftp/ideasman42/trust_header.png

- Since this is a user preference, Users with current preferences
saved won't notice any changes.



Open issues...

- Asking to reload a file is OK, but what if you haven't saved the
file? (eg, you load a new file and append an object with a driver).
  Currently the reload button is just removed in this case and you can
only choose to ignore the warning.

- There is the issue where you start a new file, add a driver --- it
wont work because auto-execution is disabled.
  ... this should probably be resolved before 2.68.

- Freestyle currently ignores auto-exec option,
  Perhaps this is OK: if you load a game and press P, it also runs
scripts even if 'Autorun' is off.
  Likewise, loading a blend file and pressing Render, will execute
freestyle scripts, optionally we could disable these too.


Note, many reasonable suggestions have been made in this thread, but
at this point I don't think its useful to reply to all.

Next Ill check on ways for users to selectively trust blend files for
their own projects so this behavior isn't annoying users.