* docs/tutorial/C/index-in.docbook: Add sections 7-9 of the "Building
applications" chapter. It's a C++/gtkmm version of a chapter in the gtk+
documentation.
* docs/tutorial/C/figures/buildapp_*.png: 3 new files. Update the old files.
* docs/tutorial/Makefile.am: Add new image files.
* examples/book/buildapp/.gitignore: Ignore gschemas.compiled.
* examples/book/buildapp/Makefile.am: Add files in step[7-9].
* examples/book/buildapp/step[7-9]: New directories with many new files.
Bug #772391