transcoding: added initial UI for watching webm/hls streams in browser.

Navigation is very primitive. clicking on the logo will step up in
channel list, or you can use the up/down arrows on the keyboard. No UI
for listing channels is available, as this is more of a test to see
what browser are working.
transcoding: minor improvements to the javascript client
transcoding: redesigned the 10-foot javascript client.

navigation is done using a keyboard (no mouse scrolling or touch events
are supported). double clicking a channel (or pressing the enter key
while being selected) will tune to a channel. the channel list can be
hidden by pressing esc or backspace, and brought back by pressing enter.
page-up and page-down are also supported.
transcoding: added missing eye candy for js client
html5video: fixed root keyboard handler for devices with VK_ENTER other than the usual one.
html5video: moved index file into tvheadend
html5video: display messages describing the state of the video element.
html5video: detect errors on the source element (tested in ff & opera)