Log Message:
Update to vte 0.20.0.

0.20.0
=======
- Support using a real bold font instead of pseudo-bolding
- Respond to fontconfig configuration changes
- Bugs fixed in this release:
    Bug 54926   Should try bold version of font before pseudo-bolding
    Bug 570208  vte fails to build outside source tree
    Bug 548272  Fix output of CSI 13,14, 18-21
    Bug 565688  [gnome-pty-helper] using openpty in a bad way
    Bug 566795  VTE fails to build in trunk
    Bug 524170  Support initc terminfo capability and change-cursor-color
    Bug 566730  vte_terminal_set_color_cursor() calls invalidate_all but
                 it doesn't have to
    Bug 565679  alloca is discouraged
    Bug 565675  typo in configure.in cause ncurses checking fail
    Bug 565663  compile failure because use static function in another .h
                 file
    Bug 575398  configure warns about term.h under OpenSolaris
    Bug 574616  "real" transparency not working from python bindings
    Bug 574025  Crash in _vte_terminal_insert_char