Properly expose TMTag which already contains documented members.

Don't use wildcards that can catch generated files.

While at it, also avoid Doxygen picking up those generated files.

This allows GI-based plugins to traverse/inspect the array and consequently
Geany loaded tags.

tm_tag.h and tm_parser.h contain documented symbols so doxygen shall process
them.

It's members are already documented so it's kind of half-exported anyway.
Since geanygendoc already uses the structure (and I plan on writing a plugin
that requires it too) just make it official.

Broken in #966.

Improve README

No behavioral changes.

Closes #1074.

X-Universal-CTags-Commit-ID: 91c6773373864da345a7a9e0f5bd01a25588471c

Fixes #756.

Privatize global and publicize docs

Fix signals for GI

Combine the libraries from the GTK3 bundle with GTK from the GTK2 one
to get newer GLib & co for GTK2 builds.

If possible, register signals with the proper argument types (boxed or gobject).
This is required for successful introspection of the signals and important
for GI-based plugins.

As for the marshallers, if available use a predefined one from glib. Otherwise
use the generic marshaller available since 2.30 (in theory all signals could
use that one but it has a bit of overhead).

This builds on the gboxed conversions of earlier commits.

This also bumps the minimum glib requirement.
 - g_cclosure_marshal_generic requires 2.30 (if NULL is passed as marshaller
   to g_signal_new())
 - G_TYPE_KEYFILE requires 2.32

geany.desktop.in: Add Keywords field entry

Fix undo of line end type change

Simply call ui_update_statusbar() and ui_document_show_hide() like in
other undo actions.

At the moment undo of line end type change only undos the changes made
in the document but the different line ending settings remains active.

This patch fixes the issue by combining the line end scintilla undo action
with a new UNDO_EOL action responsible for updating the line ending
settings.

Fixes #409

Updated scintilla_changes.patch accordingly