Fixes for bugs #310 & #311

[gloriajjl]

No description provided.

[elpiankova]

@gloriajjl Were all cases from #310 fixed?
Second case doesn't work still:

• Empty result for Potential, no error in server logs:
  [14/Jun/2019 14:09:32] "GET /en/api/data/?space_project=1&time_begin=1314662400&time_end=1351728000&polygon=MULTIPOLYGON(((-180+-1,180+-1,180+10,-180+10,-180+-1))) HTTP/1.0" 200 52

[elpiankova]

@gloriajjl About saving Quicklooks (#311 ) after these commits I don't see message "Quicklook is not completly loaded yet!", but still the image isn't saved in my computer

[elpiankova]

Fixes about bugs #310 and #311 (calibration I commented in another pull request) seem fine, but I have problems - see comments above

[elpiankova]

@gloriajjl Quicklook файлы-картинки сохраняются, но у меня они пустые - белый прямоугольник

[gloriajjl]

а так?