updated weewx-svg2png and weewx-sqlupload for WeeWX5.5

[Karen K]

I adopted the new stop event feature within report generation to the the following WeeWX extensions:

• SQL upload generator
  
• SVG to PNG converter
  

If you see error messages regarding report generators after updating to WeeWX 5.5 (not only for those two extensions), please also refer to issue #1107.