[Linux] os-release: unescape quotes / backslashes
The os-release specification states that single quotes, double quotes
and backslashes are supposed to be escaped with \. Unfortunately
I missed this in my original commit 7a9aa6f5d9ac8df1c79eb06ed63bce8af162c3ba.

http://www.freedesktop.org/software/systemd/man/os-release.html
Expose ACTION_FOO, ICON_TYPE_FOO and KEY_CODE_FOO to addons
Added JSONRPC.NotifyAll as a built-in function
fixed: compile with old versions of libdbus that don't have DBUS_TYPE_UNIX_FD defined
[rbp] Add streamsilence option for hdmi

This adds a (mostly) dummy audio engine for Pi which supports drain allowing the
stream silence gui option to appear.
The OnSettingsChange callback enables or disables the stream silence on the GPU.

Enabling this keeps the receiver awake, and avoids losing the first couple of
seconds of audio at start of playback.
Requires updated firmware.
changed: Don't allow change of volume amplification with passthrough audio
settings: fix updating skin-related settings spinners
properly reset skin-related settings after changing the current skin (fixes #14595)
[rbp/omxplayer] Add wait for buffers done calls
[rbp/omxplayer] Handle timeouts greater than a second
[rbp/omxplayer] Callback context pointer is not needed once in the class
[rbp/omxplayer] Avoid state change when already in loaded
[rbp/omxplayer] Remove warnings from event logging calls
[rbp/omxplayer] Add more event logging
[rbp/omxplayer] Signal bad state on decode error

Also abort timeouts early when in bad state
[rbp/omxplayer] We should block until all buffers are released
[rbp/omxplayer] Load OMX dll just once

On Pi xbmc isn't usable without OMX (used for video, audio, image encode and decode),
so rather than loading dll with every component, just load it once at initialisation and assume it's there
[rbp/omxplayer] Reset more state variables on Initialize

The component shouldn't remember any state from before the Initialize
Merge pull request #3356 from popcornmix/streamsilence

[rbp] Add streamsilence option for hdmi
[rbp/omxplayer] Replace jpeg parsing with cheaper byte aligned accesses

All the parsing is byte aligned which can be done about ten times faster
than bit based parsing.

Also remove the unused PNG parsing