cleaned up Makefile
renamed ModeDef::mode_line function pointer to get_mode_line
fixed some sparse warnings
use c99 syntax in video.c and image.c
added EditBuffer::offset for buffer parsing
added state variables QEmacsState::it, QEmacsState::ignore_spaces,
QEmacsState::mmap_threshold
support variables in config file, strings can be delimited with ' and "