Fix the "Could not import extension rst2pdf.pdfbuilder" error in readthedocs
Fix the "Could not import extension rst2pdf.pdfbuilder" error in readthedocs

usharesoft/hammr,emuus/hammr,usharesoft/hammr,segalaj/hammr,segalaj/hammr,MaxTakahashi/hammr,emuus/hammr,MaxTakahashi/hammr