PROTON-444: port internal store from C implementation

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1540104 13f79535-47bb-0310-9956-ffa450edef68
fixed bug in link error reporting/recovery

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1540190 13f79535-47bb-0310-9956-ffa450edef68
bumped version to 0.6

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1540191 13f79535-47bb-0310-9956-ffa450edef68