Updates the key maps. During this I noticed that the dream keymap didn't have all of the media buttons like the sapphire key map...! So this is now changed to match.
BUG=1779435
Automated import of CL 145382
Note that this also fix a bug where the SD Card image was not properly locked in the previous implementation.
Allow the http-proxy support code to actually manage to receive chunked encoding data, instead of complaining needlessly.
Introduce a new CharBuffer object that is used indirectly by "-radio <hostdevice>" and "-gps <hostdevice>" options
Add new documentation for QEMUD and CharDriverState objects
Update the Audio documentation with ASCII graphics (because I'm an artist too)
BUG=1750126,1731936
Automated import of CL 144595