0.34.11 import: change 1

0.34.11 has updated source code included, which is not yet checked
into Baughn's repo.
adding the 4 self-contained non-whitespace changes in separate commits.
0.34.11 import: change 2
0.34.11 import: change 3
0.34.11 import: change 4
[Revert me\!] Remove lambdas because I don't feel like upgrading to wheezy right now
Support building without GTK+2.0.
Fix missing includes. (They used to be included by GTK2.)
make GL optional
scons: make building of GL stuff optional
remove unneeded gl headers include
graphics.h: likewise
enabler: make GL header usage optional
curses.h: remove gl header inclusion
fix SConscript
curses.h: only use ncursesw when we have it
only uses curses stuff if we want to use it
fix missing dlfcn.h include
fix remaining unconditional ncurses usage
fix textures.cpp
make it possible to disable curses with scons disable-curses=1