[bugfixes] removed segfault crash
[bugfixes] fixed crash in demo app

- unsafe multi-threaded access to ncurses window structures
[untracked] updated simple logger
[untracked] updated refine_log.sh script to handle new log file formats
ref #1830 [flush audio playout structures after rebuffering]
re #1830 [don't apply ac-sync adjustment when playback time is inferred]

- when playback time is inferred for the packet - do not apply av-sync
drift adjustment (it will be applied later for normal packets)
ref #1830 [restrict ac-sync adjustment value to maximum of 50ms]

- if audio packet is leading video for more than
MaxAllowableAvSyncAdjustment (50ms) then adjustment is set to this
value. next packets will be adjusted as well unless total drift would
be consumed
ref #1068 [libc++ vs libstdc++ handling]

- fixed forcing to use libstdc++ flag in configuration
- by default libstdc++ is used only if available by compiler
- added optional flag —with-libc++ which enforces to use libc++ instead
of libstdc++
[untracked] changed library build number to library version string