KNemo 0.6.0

* backend changes:
- added IPv6 support
- sysfs and nettools backends replaced with a netlink backend on Linux and a more general backend for BSD (currently only tested on FreeBSD). Note: BSD backend currently lacks wireless support.
- polling periods can range from 0.1 to 2 seconds
- added notifications for when an interface becomes available/unavailable
- kill custom commands that are still running when KNemo closes

* statistics changes:
- added weekly statistics
- monthly statistics can act like "billing periods". Billing periods can start on an arbitrary day and can span 1-6 months.
- optional notification if a billing period's traffic exceeds a threshold

* ui changes:
- improved icon theming modeled after the network status icons in the freedesktop.org icon naming spec
- added a text icon theme that reports upload/download speeds in the tray
- status dialog supports multiple IP addresses per interface
- redesigned config dialog; should reduce information overload
- plotter properties are saved per interface and accessible by right clicking a plotter