Issue viewing default PDF with HTTPS sites

[prabhanshu]

pdfXBlock uses http protocol for its default pdf url, which block this pdf to be viewed at https sites
default="http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf" at
https://github.com/MarCnu/pdfXBlock/blob/master/pdf/pdf.py#L26

We have to disable the protection to view this pdf

Screenshot when https protection is enabled