move stack source into subdir
add llvm and clang, both from svn rev 193056
add untarred boolector
add untarred lingeling
add CMake files
build llvm with options necessary for STACK
move lit from lib to 3rdparty
remove boolector and lingeling tarballs
update README and INSTALL - now markdown, add some CMake info
obfuscate the 'int' email address slightly
small update to README.md
oops, the set() command needs both parens
oops, renamed config.h -> stack_cfg.h
inch closer to working with CMake