extmod/modwebrepl: Make GET_FILE operation non-blocking.
extmod/modwebrepl: Make GET_FILE operation non-blocking.

In the sense that while GET_FILE transfers its data, REPL still works.
This is done by requiring client to send 1-byte block before WebREPL
server transfers next block of data.

mhoffma/micropython,dmazzella/micropython,puuu/micropython,bvernoux/micropython,chrisdearman/micropython,puuu/micropython,Timmenem/micropython,tralamazza/micropython,micropython/micropython-esp32,alex-robbins/micropython,adafruit/micropython,Timmenem/micropython,matthewelse/micropython,torwag/micropython,jmarcelino/pycom-micropython,dxxb/micropython,trezor/micropython,MrSurly/micropython,micropython/micropython-esp32,oopy/micropython,pozetroninc/micropython,lowRISC/micropython,micropython/micropython-esp32,deshipu/micropython,cwyark/micropython,hosaka/micropython,tobbad/micropython,AriZuu/micropython,chrisdearman/micropython,henriknelson/micropython,deshipu/micropython,tuc-osg/micropython,trezor/micropython,selste/micropython,dxxb/micropython,lowRISC/micropython,bvernoux/micropython,tralamazza/micropython,henriknelson/micropython,mhoffma/micropython,ryannathans/micropython,hiway/micropython,matthewelse/micropython,torwag/micropython,tobbad/micropython,MrSurly/micropython,MrSurly/micropython-esp32,Peetz0r/micropython-esp32,adafruit/circuitpython,kerneltask/micropython,cwyark/micropython,TDAbboud/micropython,PappaPeppar/micropython,toolmacher/micropython,AriZuu/micropython,Peetz0r/micropython-esp32,mhoffma/micropython,chrisdearman/micropython,dmazzella/micropython,swegener/micropython,hiway/micropython,selste/micropython,cwyark/micropython,redbear/micropython,alex-robbins/micropython,adafruit/circuitpython,alex-robbins/micropython,trezor/micropython,lowRISC/micropython,pramasoul/micropython,ryannathans/micropython,HenrikSolver/micropython,AriZuu/micropython,pozetroninc/micropython,torwag/micropython,hosaka/micropython,turbinenreiter/micropython,turbinenreiter/micropython,redbear/micropython,pramasoul/micropython,SHA2017-badge/micropython-esp32,micropython/micropython-esp32,MrSurly/micropython,MrSurly/micropython,kerneltask/micropython,blazewicz/micropython,adafruit/micropython,AriZuu/micropython,dxxb/micropython,ganshun666/micropython,micropython/micropython-esp32,HenrikSolver/micropython,tuc-osg/micropython,hosaka/micropython,infinnovation/micropython,matthewelse/micropython,swegener/micropython,ryannathans/micropython,deshipu/micropython,ganshun666/micropython,Peetz0r/micropython-esp32,adafruit/circuitpython,oopy/micropython,pozetroninc/micropython,pfalcon/micropython,tralamazza/micropython,TDAbboud/micropython,kerneltask/micropython,blazewicz/micropython,MrSurly/micropython-esp32,HenrikSolver/micropython,torwag/micropython,adafruit/micropython,dxxb/micropython,PappaPeppar/micropython,swegener/micropython,deshipu/micropython,swegener/micropython,turbinenreiter/micropython,ganshun666/micropython,redbear/micropython,cwyark/micropython,tuc-osg/micropython,kerneltask/micropython,redbear/micropython,alex-march/micropython,ryannathans/micropython,dxxb/micropython,tuc-osg/micropython,oopy/micropython,bvernoux/micropython,SHA2017-badge/micropython-esp32,alex-march/micropython,infinnovation/micropython,torwag/micropython,pozetroninc/micropython,MrSurly/micropython-esp32,adafruit/circuitpython,hiway/micropython,bvernoux/micropython,PappaPeppar/micropython,Peetz0r/micropython-esp32,trezor/micropython,pozetroninc/micropython,matthewelse/micropython,trezor/micropython,oopy/micropython,tralamazza/micropython,lowRISC/micropython,SHA2017-badge/micropython-esp32,hosaka/micropython,turbinenreiter/micropython,puuu/micropython,SHA2017-badge/micropython-esp32,ryannathans/micropython,toolmacher/micropython,TDAbboud/micropython,mhoffma/micropython,matthewelse/micropython,SHA2017-badge/micropython-esp32,pfalcon/micropython,puuu/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,jmarcelino/pycom-micropython,adafruit/micropython,jmarcelino/pycom-micropython,deshipu/micropython,selste/micropython,swegener/micropython,selste/micropython,pramasoul/micropython,tobbad/micropython,chrisdearman/micropython,pramasoul/micropython,dmazzella/micropython,ganshun666/micropython,toolmacher/micropython,alex-march/micropython,tuc-osg/micropython,puuu/micropython,tobbad/micropython,oopy/micropython,MrSurly/micropython,infinnovation/micropython,blazewicz/micropython,alex-robbins/micropython,blazewicz/micropython,alex-robbins/micropython,PappaPeppar/micropython,Timmenem/micropython,TDAbboud/micropython,matthewelse/micropython,toolmacher/micropython,chrisdearman/micropython,MrSurly/micropython-esp32,PappaPeppar/micropython,Timmenem/micropython,selste/micropython,ganshun666/micropython,kerneltask/micropython,TDAbboud/micropython,henriknelson/micropython,HenrikSolver/micropython,alex-march/micropython,cwyark/micropython,pfalcon/micropython,MrSurly/micropython-esp32,HenrikSolver/micropython,hosaka/micropython,adafruit/micropython,toolmacher/micropython,AriZuu/micropython,henriknelson/micropython,jmarcelino/pycom-micropython,lowRISC/micropython,alex-march/micropython,infinnovation/micropython,dmazzella/micropython,infinnovation/micropython,pramasoul/micropython,turbinenreiter/micropython,mhoffma/micropython,jmarcelino/pycom-micropython,Peetz0r/micropython-esp32,Timmenem/micropython,redbear/micropython,pfalcon/micropython,tobbad/micropython,pfalcon/micropython,hiway/micropython,blazewicz/micropython,henriknelson/micropython,hiway/micropython