0.8.4

This is a long overdue, but still relatively
minor bug fix release.  There have been some small features
since 0.8.3, too. Since this release is overdue, a lot of these
changes aren't *new* and distros may already be shipping them.

Changes include:

- plymouth client hang fix
- support for different fonts in the label control
- updates to work with newer libpng
- set-default-theme quoting fixes
- better support for serial consoles
- support for 'ignore-keystroke' and 'hide-message' commands
- better integration with upstart and systemd
- fd leak fixes
- more configuration options for throbgress plugin
- better conditionalize drm build requirements
- terminal fixes
- drm renderer fixes
- x11 renderer fixes
- improved debug logging output
- support corner cases for animations better
- use /dev/fb0 instead of /dev/fb for framebuffer
- change how we do socket communciation between client and daemon
- add --kernel-command-line option to override /proc/cmdline
- miscellaneous other changes
- buildsystem fixes