TODO List
* Modularisation
** separating gtk support and make it a build-time option
** Modularise route-table parsing.
* The restriction to the local link is essentially arbitrary:
extending the program to check the transport ("ping"!) to
any ip address should not be too difficult: for distant
hosts some timeout conditions may be required.
* Make it portable: check ping and netstat options and
output on other systems.
Too many others things!
* gnome applet?!
* gtk configuration
* multiple interfaces?
* parsing the output of one long-lived ping process instead
* dealing with multiple routers on link
* shortcuts, eg C-q
* ppp control
** if ppp link is broken, option to restart it automatically