Nextrtc Signaling Server Versions Save

- NextRTCConversation will expose information about creator and members
- Close reason will not be returned in event
- Content in event will not be Optional anymore (you'll get content or empty string)
- Server will be closeable (all thread pools will be closed, and connection released)

Any websocket implementation can be used <3

• Updated pom and readme =x=>- Removed dependency to WebSocket JSR-356
• New conversation type MESH_WITH_MASTER (when master leaves then conversation will be destroyed)

log4j has been replaced by slf4j

    - Improved message sender (errors will be send only once whereas normal messages will be retried 3 times)
    - In broadcast conversation participant will received newJoined signal with master data
    - Ping will not start immediately after member is joined
    - When session is closed message will not be send through it
    - Each send will try at least 3 times before failing
===>- Introduced message sender instead of method send in InternalMessage
    - Introduced parallel model inside conversation
    - Changed log level
    - Synchronization on join signal
    - Fixed version of dependencies
    - Performance tests
    - Used Synchronous communication instead of Asynchronous
    - Hanging connections #28 

- Changed structure of Exceptions
- Added property nextrtc.join_only_to_existing to decide whether join conversation should thrown an exception when conversation exists or create a new one.
- Changed pom version policy

- Extracted EndpointConfiguration
- Updated README.md
- NextRTC can be run as Spring app or as Standalone server
- Daggered project
- Refactored way of creation beans - Added factories, extracted interfaces and prepared 2 configuration. First for manual - standalone mode, second for Spring mode
- Lomboked again project
- Removed joda-time from dependency (Zoned Date time is used instead)

fixed problem with flushing server response

• PingTask will not send a messages when session is closed (now it could sometimes)
• EventDispatcher will catch all Exception, and allow to process rest of handlers (now handlers were executed to the first exception in chain)
• Improved logging for unexpected situation, stacktrace will be logged in DEBUG level
• One member will be able to create or join to only one conversation
• Candidates will be exchanged even for broadcast conversation
• Added new method to SignalResolver (addCustomHandler) which allows you to add your custom signal
• Added actor test for TEXT message

• Added new signal END which is send when broadcaster will exit from broadcast conversation
• Prepared ActorTests where Actor play role of js client
• Added ERROR signal. Improved exception handling. When exception occurs it'll be convert to normal message and connection will be broken
• Improved logging (Overridden toString)
• CREATE signal will return in custom type of created conversation
• JOIN signal works in the same way as CREATE signal when conversation doesn't not exists
• removed js file from this project (new project for js will be created)

• New signal 'newJoined' added to separate two case when someone has joined to conversation and to inform rest of people from conversation about new joiner
• Added js leave method which close websocket connection and stop streaming
• Added default behavior to TEXT message, when message TEXT is sent without recipient, then message will be broadcasted to all conversation members
• Connection context has new feature, ICE candidates can be filter out when they didn't came from broadcaster (master in connection)
• Added broadcast conversation type
• Added policy to handle certain signals
• Expanded API of event new method content has been added (text messages can be stored in java app)
• Added new signal type TEXT (to transfer text messages between communication members)
• Delomboked project - too many questions were connected with building project