modern types
rebar support
add .app and .appup files - need to revisit these later
add a few more things to ignore
simplify expression in exmpp_jid:bare/1
add expat to LDFLAGS
Use exmpp.app.src
Merge remote-tracking branch 'github/master'
Modify rebar.config to deal with upgraded rebar
Specify .c files in rebar.config