Vte is GNOME 2's virtual-terminal emulation widget.

Overview of changes betwen 0.11.20 and 0.11.21:

0.11.21 - Revert change introduced in 0.11.19 that made vte very unresponsive with tall terminal windows. (bug #333776)
- Step up COALESCE_TIMEOUT and DISPLAY_TIMEOUT from 2ms to 10ms. This is more compatible with the update timeout that we are doing at 25ms, but needs testing.