new version with fix for pynng 0.7.2;
changed pem to crt;
fixed c-strings;
added offset and length arguments to setParameterMsg;
fixed resubscription;
added automatic reconnect and resubscribe;
fixed getParameterList;
updated messages; updated version;
fixed string encoding/decoding
fixed installation with pip
made better file name for the tree cach;
fixed path concatenation across different OS; added __version__;