Fix #1: add README
Link to ufo-filters
Fix execution in non-Python environments

The Python thread state can only be saved when we are actually running inside
something that looks like Python. Hence, we check first and save then.
Require CMake 2.6 in all directories
Make ufo-core fit for Clang
Ignore all kinds of build directories
Add GLIB version guards

-Make sure we don't use any new features above GLib 2.30
-Ubuntu 12.04 uses glib 2.32.x which requires GLIB_VERSION_2_26 to
 be the smallest compile target -> bump minimum version to 2.26
Fix test execution problem on openSUSE

For some reason, locking across two calls was not working on openSUSE-based
systems. This change replaces the simple lock scheme with a condition-based
approach.
Abstract away communication into interface

* Create generic interface ufo_messenger_iface
* Move all zmq_* stuff into ufo_zmq_messenger that implements that
  interface
* also fixes a bug that happened when closing the zmq_socket from
  another thread by introducing a special TERMINATE message that
  will kill ufo-daemon
Fix bug: no plugin name is sent to remote nodes
Add MPI support