Prevent exit() in console from exiting Geany

TODO: see about setting sys.excepthook to trap unhandled exceptions
in actual plugin code and rather than dumping to debug messages (or
exiting, in the case of SystemExit exception), present a dialog showing
a user-friendly message with option to see the details/traceback.
Fix build with Automake >= 1.12
Don't error out on Automake warnings

Automake tends to add new warnings or change which are enabled by some
options between versions, so drop -Werror from the default Automake
flags.  Users can always pass the option manually when invoking
Automake.
Fix source files list
Don't call LT_INIT before AM_PROG_AR
Fix some docs in the document module
Merge pull request #14 from ParisLiakos/master

Fix some docs in the document module
Fix a couple typos in document property getter function (oops)

Thanks to Pavel Roschin for finding them.
Add GLib logging support with python wrapper functions

Wrap g_log() from GLib (unfortunately it is not provided by PyGTK) and
add a convenience wrapper in Python to behave like a
logging.Logger object.
Additionally, in geany.Plugin this wrapper is instantiated on Plugin
initialization and LOG_DOMAIN is set accordingly.
This enables GeanyPy plugins to log through GLib's logging
system like any other plugins and Geany itself do and so log
messages will be visible in Help->Debug Messages.
Merge branch 'eht16/glib-logging'
merged logger