Setting tag plcapi-5.3-11

Setting tag plcapi-5.3-11
mostly issued for the R2lab deployment
*** major
* dots allowed in login_base and slice name
* new lease filter 'day'
*** minor
* more explicit message in case of overlapping resas
* bugfix: escaping unicode in xml
* GetLeases allowed to anonymous callers
*** miscell
* use plain json library