* [QSIM_MOD,SC] Use of PGC's USER_DB.
* [WEBQR_BUILD,SC] Imported several predicates from WEBQR_WEB.
* [WEBQR_UC,SC] Use of new webqr_create_model/1.
* [WEBQR_WEB,FIX] circle and line HTTP handlers relatice to webqr path.
* [WEBQR_WEB,SC] Simplified user registrarion by using USER_DB (PGC).
* [WEBQR_WEB,FIX] JSON mismatch in REST processing.
* [WEBQR_WEB,DOC] Added documentation.
Merge branch 'master' of https://github.com/wouterbeek/WebQR