fix fetching content info (danikula#27)

fix self-pinging (danikula#24)

🐛 fix Content-Range header for partial response according to http spec (

http://bit.ly/content-range)

add disk usage limits (total cache size, total files, unlimited) dani…

…kula#5

add seeking video support (danikula#21) and fix streaming while cachi…

…ng (danikula#17)

hide 'publish.sh'

ping proxy after starting to make sure it works fine

fix offline work

update 'whats new' section in readme

optimize featching source data