Tornado's StaticFileHandler now supports content streaming, use that instead of our own implementation
Tornado's StaticFileHandler now supports content streaming, use that instead of our own implementation

Also allow for definition of access validation and serving as attachment though.

Hopefully also fixes #606, since that was possibly called by our own implementation of content streaming, which now has been removed completely.

Salandora/OctoPrint,Voxel8/OctoPrint,Javierma/OctoPrint-TFG,JackGavin13/octoprint-test-not-finished,MaxOLydian/OctoPrint,ryanneufeld/OctoPrint,mayoff/OctoPrint,sstocker46/OctoPrint,EZ3-India/EZ-Remote,CapnBry/OctoPrint,Salandora/OctoPrint,eliasbakken/OctoPrint,Jaesin/OctoPrint,nicanor-romero/OctoPrint,jneves/OctoPrint,nicanor-romero/OctoPrint,shaggythesheep/OctoPrint,spapadim/OctoPrint,punkkeks/OctoPrint,shohei/Octoprint,ymilord/OctoPrint-MrBeam,senttech/OctoPrint,alex1818/OctoPrint,ryanneufeld/OctoPrint,punkkeks/OctoPrint,Jaesin/OctoPrint,leductan-nguyen/RaionPi,chriskoz/OctoPrint,MoonshineSG/OctoPrint,sstocker46/OctoPrint,leductan-nguyen/RaionPi,eliasbakken/OctoPrint,beeverycreative/BEEweb,foosel/OctoPrint,mrbeam/OctoPrint,senttech/OctoPrint,dragondgold/OctoPrint,alex1818/OctoPrint,uuv/OctoPrint,Jaesin/OctoPrint,masterhou/OctoPrint,ErikDeBruijn/OctoPrint,ErikDeBruijn/OctoPrint,MoonshineSG/OctoPrint,EZ3-India/EZ-Remote,mcanes/OctoPrint,beeverycreative/BEEweb,bicephale/OctoPrint,alex1818/OctoPrint,senttech/OctoPrint,Salandora/OctoPrint,EZ3-India/EZ-Remote,markwal/OctoPrint,masterhou/OctoPrint,shohei/Octoprint,bicephale/OctoPrint,nickverschoor/OctoPrint,spapadim/OctoPrint,eliasbakken/OctoPrint,MaxOLydian/OctoPrint,ryanneufeld/OctoPrint,Salandora/OctoPrint,JackGavin13/octoprint-test-not-finished,EZ3-India/EZ-Remote,uuv/OctoPrint,CapnBry/OctoPrint,shaggythesheep/OctoPrint,chriskoz/OctoPrint,Mikk36/OctoPrint,bicephale/OctoPrint,ymilord/OctoPrint-MrBeam,mayoff/OctoPrint,senttech/OctoPrint,mcanes/OctoPrint,chriskoz/OctoPrint,Javierma/OctoPrint-TFG,Mikk36/OctoPrint,shohei/Octoprint,mrbeam/OctoPrint,SeveQ/OctoPrint,foosel/OctoPrint,JackGavin13/octoprint-test-not-finished,leductan-nguyen/RaionPi,Mikk36/OctoPrint,MoonshineSG/OctoPrint,beeverycreative/BEEweb,chriskoz/OctoPrint,markwal/OctoPrint,jneves/OctoPrint,shohei/Octoprint,leductan-nguyen/RaionPi,jneves/OctoPrint,javivi001/OctoPrint,nicanor-romero/OctoPrint,beeverycreative/BEEweb,JackGavin13/octoprint-test-not-finished,ErikDeBruijn/OctoPrint,eddieparker/OctoPrint,dansantee/OctoPrint,SeveQ/OctoPrint,bicephale/OctoPrint,ymilord/OctoPrint-MrBeam,markwal/OctoPrint,eddieparker/OctoPrint,ymilord/OctoPrint-MrBeam,eddieparker/OctoPrint,foosel/OctoPrint,mcanes/OctoPrint,Javierma/OctoPrint-TFG,nickverschoor/OctoPrint,Skeen/OctoPrint,dansantee/OctoPrint,nickverschoor/OctoPrint,mayoff/OctoPrint,CapnBry/OctoPrint,dansantee/OctoPrint,Javierma/OctoPrint-TFG,dragondgold/OctoPrint,dragondgold/OctoPrint,sstocker46/OctoPrint,javivi001/OctoPrint,shaggythesheep/OctoPrint,spapadim/OctoPrint,Jaesin/OctoPrint,shohei/Octoprint,mrbeam/OctoPrint,MaxOLydian/OctoPrint,ryanneufeld/OctoPrint,MoonshineSG/OctoPrint,foosel/OctoPrint,Skeen/OctoPrint,Voxel8/OctoPrint,javivi001/OctoPrint,nickverschoor/OctoPrint,ymilord/OctoPrint-MrBeam,CapnBry/OctoPrint,Voxel8/OctoPrint,Skeen/OctoPrint,uuv/OctoPrint,masterhou/OctoPrint,punkkeks/OctoPrint,SeveQ/OctoPrint