* implemented lifecycle-bound functions in caspar::io::connection
* refactored caspar::io::connection to avoid circular references
* moved delimiter-chunking logic out from AMCPProtocolStrategy and CIIProtocolStrategy. They now depend on being wrapped by a delimiter_based_chunking_strategy
* refactoring of AMCPProtocolStrategy::Parse and the AMCPCommands
* implemented LOCK-command to protect a channel from accidental access
Merge branch '2.1.0' of https://github.com/CasparCG/Server into 2.1.0

Conflicts:
	protocol/amcp/AMCPProtocolStrategy.cpp
Merge branch '2.1.0' of https://github.com/CasparCG/Server into 2.1.0
* made lifecycle_bound_objects_ thread-safe
* the psd-importer now extracts timeline-data
Merge branch '2.1.0' of https://github.com/CasparCG/Server into 2.1.0