Merge pull request #10 from diegozea/master

Change _RL_INITIALIZED from macro to function
changed so it builds dylib instead of so shared lib file (needed on Mac)
Merge pull request #13 from robertfeldt/dylib_build

changed so it builds dylib instead of so shared lib file (needed on Mac)
add extension name, needed for mac
use ENV variable
disable READLINE, causing segfault
rtype should be Uint
remove the debug message
Merge pull request #16 from randy3k/master

bug fix for mac and current julia version