freshplayerplugin v0.3.3

• add implementation of PPB_NetAddress;1.0 inferface;
• add "noaudio" backend which doesn't output any sound, but provides synchronization events [1];
• callbacks are now called on the same message loop they were passed from, not on main plugin thread as before;
• own configuration parser is used, libconfig-dev is no longer required [2];
• to mitigate interlocking issues, Javascript code is no longer called from NPP_SetWindow() handler;
• -fvisibility=hidden option is no longer used for executables (should fix build on mipsel);
• plugin file name is changed to libfreshwrapper-flashplayer.so [3].

[1] Flash relies on audio card to measure time, which could prevent video from playing if no sound card was available.
[2] Across distros, libconfig have two incompatible versions.
[3] Scripts on Twitch.tv use filename in version detection, and having "pepper" in a name breaks user interface. See #273 for details.