duty-roaster-0.1.0

It has been some time since the last release, mainly because i didn't have that much time. Don't expect any spectacular changes since the last release. However, 'legal periods' are no longer specified by start weeks but by partial dates - thus the format of the save files has changed one more time. Besides, duty-roaster now compiles with gcc-4.1 and supports gnu gettext. Note that the file format is garantied to stay compatible for the 0.1.x versions, which will be around for some time.