GXemul Code2

Adding a unit test for doubles in StateVariable::SetValue, for values such as 1e-100.

Some more work on the GTKMM GUI: the debug output window now
shows debug messages and commands being executed.

Instead of loading binaries into an AddressDataBus, they are
now loaded into a Component, which, if it has a "pc" state
variable, is set to the entry point. Starting gxemul with
-E testmips test/FileLoader_ELF_MIPS actually attempts to
start running the binary now :-)

Catching std::exception at the outermost level, in order to
print a reasonable message if the application crashes.

The GTK+ GUI is not supposed to be preliminary when 0.5.0 is released. It will be an official feature.

Beginning on a FileLoader class, for loading binaries (e.g.
ELFs). Also adding a test/ directory, where small test files
used for unit tests may be stored. ELF program segments are
loaded, but no additional information yet (entry point etc.).

Show expected and actual uint64_t values in hex, for increased readability.

The GTKMM GUI EmulationDesignArea now shows some dummy circles
(one for each component in the emulation setup).

Removing all old CVS $Id$ tags; they are not useful anymore.

Implementing basic support for updating the UI when some things
change: Undo/Redo-applicability, the name of the emulation, and
the RunState. (As UI::UpdateUI().)