1. add seekgen to recording server, crtmpserver do not need to generate meta/seek files it self
2. modification of on-command connect, some part of modification for on-command connect
3. update storage file info from vector to list to support threaded video transcode
4. support threaded transcode video to add thread_pool for this feature
Merge branch 'release'

Conflicts:
	recording_server2.0/build-linux/Makefile
	recording_server2.0/storage_clean/StorageCleanService.cpp
	recording_server2.0/stream_recorder/DeviceStorageInfo.cpp
	recording_server2.0/stream_recorder/DeviceStorageInfo.h
	recording_server2.0/stream_recorder/StreamWriter.cpp