now compiles with gtk3 (still deprecation warnings)

changed "pp->frame->parent" to
gtk_widget_get_parent(pp->frame)

using GDK_KEY_<key>
gitignore compiled binary
fix use of deprecated gdk_display_get_pointer
fix deprecated font chooser
manpage: Mention gtk3 branch and known bugs.
README: Refresh.
Completely removed caching, including settings and docs.

a) We're not sure if we really need it after the switch to Gtk3 and
   cairo.

b) As long as we're in the process of switching to Gtk3, I want things
   to be as simple as possible. Caching introduces code complexity.
   Let's get the basics to work and then start to optimize things.
use mouse button constants
use pkg-config instead of xml2-config
fix typo
Use GtkDrawingArea to render the PDF, directly with poppler+cairo.
Replaced GtkVBox with GtkBox.
refactor makefile
make: Fixes for FreeBSD.

Conflicts:
	makefile
Added install target to makefile

Conflicts:
	makefile
make: Follow INSTALL_* convention.

Conflicts:
	makefile
make: Added support for prefix, bindir, etc.
Renamed makefile -> Makefile.

Most people appear to be using "Makefile" instead of "makefile" and it's
somewhat recommended by GNU:

http://www.gnu.org/software/make/manual/html_node/Makefile-Names.html
make: Added target "dist".
make: Fixes for OpenBSD.

OpenBSD's "install" does not know "-D". I figured the easiest way is
simply a "mkdir -p". I know that's not recommended. See my comment,
though:

	Note: We only support GNU, OpenBSD and FreeBSD right now and all
	of them know "mkdir -p".