net-im/corebird: Update rest dependencies for corebird

We need a newer version of the rest library in order for pictures to be
posted properly with corebird
net-im/corebird: Add gstreamer flag for enabling video

Thanks to Mark R. Pariente for adding this into his version of the 0.8
ebuild [here](https://506984.bugs.gentoo.org/attachment.cgi?id=381032)
net-im/corebird: Remove extraneous KEYWORDS line in 0.8 ebuild
net-im/corebird: Bump 0.8 ebuild to 0.8-r1