Add function that checks fermi sources within the real 90% contour

[azegarelli]

Update with respect to the recent release, to check Fermi sources within the actual contour.
The user can choose, through the option check_fermi_sources_box, if checking from Fermi sources within the rectangular error box or the actual contour available from the map.

I've done some tests on these options installing in realtime containers the SkyReader version corresponding to this branch.

Example for the last alert (plot below)

Output setting check_fermi_sources_box=True

SkyMist  [18:06]
[skymist@39b278d8ed5b] --
Fermi sources inside 90%:
    - FL16Y J2035.0+3632
      RA [deg]: 308.768 deg
      Dec [deg]: 36.539 deg
      Angular distance from IceCube best fit: 0.760 deg
      Primary associated source: PSR J2034+3632
      Source classification: MSP
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:

  --- 4FGL association ---
      Source name in 4FGL: 4FGL J2035.0+3632
      Primary associated source: PSR J2034+3632
      Source classification: MSP
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:
      RA [deg] in 4FGL: 308.7571105957031
      DEC [deg] in 4FGL: 36.53710174560547
      Light Curve Repository: https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J2035.0+3632

    - FL16Y J2030.0+3641
      RA [deg]: 307.505 deg
      Dec [deg]: 36.692 deg
      Angular distance from IceCube best fit: 1.451 deg
      Primary associated source: PSR J2030+3641
      Source classification: PSR
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:

  --- 4FGL association ---
      Source name in 4FGL: 4FGL J2030.0+3641
      Primary associated source: PSR J2030+3641
      Source classification: PSR
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:
      RA [deg] in 4FGL: 307.50860595703125
      DEC [deg] in 4FGL: 36.687198638916016
      Light Curve Repository: https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J2030.0+3641

Output setting check_fermi_sources_box=False

SkyMist  [17:27]
[skymist@90beea090bc6] --
Fermi sources inside 90%:
    - FL16Y J2035.0+3632
      RA [deg]: 308.768 deg
      Dec [deg]: 36.539 deg
      Angular distance from IceCube best fit: 0.760 deg
      Primary associated source: PSR J2034+3632
      Source classification: MSP
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:

  --- 4FGL association ---
      Source name in 4FGL: 4FGL J2035.0+3632
      Primary associated source: PSR J2034+3632
      Source classification: MSP
      Secondary associated source:
      Source classification:       TeV source?: N
      Associated TeV source:
      RA [deg] in 4FGL: 308.7571105957031
      DEC [deg] in 4FGL: 36.53710174560547
      Light Curve Repository: https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J2035.0+3632

You see that in the latter case FL16Y J2030.0+3641 doesn't appear anymore, as expected.

[blaufuss]

awesome, thanks @azegarelli