Case insensitive search in GtkTextIter

[Nacho <nacho resa gmail com>]

Hey guys,

    case insensitive search in GtkTextView has been an open RFE for almost a decade now [0].

GtkSourceView contains an implementation of this feature and with the arrival of Gtk3 (which also means ABI break for GtkSourceView3 and many of the bindings) we thought it would be a good time to propose to finally move it in GTK proper.

The reasons are the following:
The code has been stable and widely tested for several years
The api is a clear extension of the current GtkTexIter api (just an additional flag to the search functions)
This would be way better for introspection, since GtkTextIter is not an extensible object. This means that bindings could finally have iter.find(...) instead of something like GtkSource.iter_find(iter, ...)
The code is cut and pasted in a lot of projects [1], and the switch to gtk3 would be a good time for them to drop the cut&pasted code

For what I know, back in the day when the GtkSourceIter implementation was proposed for inclusion, it was rejected because implementation could be more memory efficient. However, 9 years of waiting show that a better implementation will not magically appear. Having it included means that:

api will be there for all the projects that need it and do not seem to be affected by any major performance problem
maybe trigger interest by someone who wants to optimize it (if performance is a real problem on today's machines)

If there is some agreement about this we can provide a patch moving the GtkSourceView implementation to Gtk

[0]: https://bugzilla.gnome.org/show_bug.cgi?id=61852
[1]: http://www.google.com/codesearch?q=gtksourceiter&hl=en&btnG=Search+Code