According to wps code audio_pre_ff_rewind function should be called
before any rewinding. It stops playback and automatically resumes it
after audio_ff_rewind call
So, let's add audio_pre_ff_rewind to plugin's API
Lua scipts were tested:
```lua
-- has issue with rewinding
rb.audio("ff_rewind", 0)
```
```lua
-- no issue with rewinding
rb.audio("pre_ff_rewind")
rb.audio("ff_rewind", 0)
```
Change-Id: I2ad6b9c396760b2086bc0a28633a1c80c3512739
audio_play was removed from the rocklib I assume due to inconsistent
behavior I've readded it with a check for audio paused which instead
uses rewind/ff and then resumes audio
the way to call the audio functions has changed as well
rb.audio("option", var)
so rb.audio_play(0, 0) becomes rb.audio("play", 0, 0)
audio_audio_flush_and_reload_tracks becomes
rb.audio("flushandreloadtracks")
all functions except audio("getfilepos") return the previous (or still current)
status
added audio.lua to the includes for conversion to old functions
if your script is broken by this change you simply add `require("audio")`
to the top for the old functionality
Change-Id: I364adf0c85d9c12b98cde29c26fbe5ee05b9d331