Add safety checks

[gkoz]

• Assert that GTK is initialized in constructors and free functions.
• Prevent unwinding across FFI.
• Make main_quit safe.

Fix #187 and #188

[GuillaumeGomez]

And here comes the monstruous thing... I forgot to ask : does your script takes in account the fact the macro is already called or does it just add it without checking ?

[gkoz]

The script is a fancy specialized version of grep. It will fail the test if a non-method is missing the assert. Macro invocations were added semi-automatically by a variation of that regex.

[gkoz]

This is the script, that helps me do these kinds of sweeping 'refactorings'. A long time ago when starting to tinker with rgtk I was intending to make a graphical tool in Rust for this but this script does the job mostly.

[GuillaumeGomez]

We should think about adding a repo for all these scripts, don't you think ?

[gkoz]

Dunno. The replacer script is pretty generic and spartan. Anything else?

[GuillaumeGomez]

The rustdoc-stripper when the regenerate part will be done ? Once again, it's just an idea.

[gkoz]

Yeah perhaps.
Oops, I've just tried running the examples for the first time and looks like I'll be fixing up the PRs 😨

[gkoz]

Added callback guard. This completes the safety fixes I had in mind for now.