use buffer size, fix media enclosures, fix names

- use the buffer size of downloaded media instead of content length
  (shouldv'e done so in the first place)

- allow multiple media enclosures

- replace special chars for filenames
add note about mime type detection
prefer enclosures before GUID for media
add build badge
fix module name && update deps
fix package path typo
replace github
use custom import path for neinp
fix git path in documentation
add .build.yml
use sr.ht neinp imports
fix usage in readme
initial commit