Currently, the ScintillaObject signals can't be used from python code via
gobject-introspection. This is because g-ir-scanner does not properly scan
the signals.

For signals, there is the additional requirement that parameters have are
registered GTypes. For the sci-notify signal, this can be accomplished by
boxing SCNotification.

In addition, g-ir-scanner also runs on Scintilla.h where it picks up
additional structs.

test/gi/ is updated accordingly. The test python script is enhanced
to showcase the signals (some fixes to the makefile are included as well).

Currently, the ScintillaObject signals can't be used from python code via
gobject-introspection. This is because g-ir-scanner does not properly scan
the signals.

For signals, there is the additional requirement that parameters have are
registered GTypes. For the sci-notify signal, this can be accomplished by
boxing SCNotification.

In addition, g-ir-scanner also runs on Scintilla.h where it picks up
additional structs.

test/gi/ is updated accordingly. The test python script is enhanced
to showcase the signals (some fixes to the makefile are included as well).

Avoid doc-comment in header as they are interpreted by g-ir-scanner, fix a typo,
remove empty lines, add to change log.

- remove any notion of deprecation of legacy symbol names
- make sure typelib search path is set for test program
- add separate test target to test/gi/makefile
- improve g-ir-scanner call command line
- fixed gtk2 support of test test/gi/gi-test.py

g-ir-scanner expects a certain naming scheme. Adhering gives the benefit of
automatically getting correct gobject-introspection data.

This fixes the SCINTILLA_CLASS() and IS_SCINTILLA() macros on GTK3.
No harm on GTK2, those macros are available since 2.0.

This also makes those macros more consistent with the SCINTILLA()
macro that already uses the proper GObject calls.