Version 1.1.0

• [added] clean-up mechanism for blockwise transfer state
• [added] filter when notifying observers
• [added] send and receive events to IEndPoint
• [added] support for cancelling reject messages
• [added] support for cancelling blockwise transfer
• [added] support for blockwise transfers with NON
• [updated] rename obsoleted events and properties in CoAP Message
• [updated] mark as CLSCompliant
• [updated] lazy initializing lock in a request to avoid locks if possible
• [updated] collection classes for .NET 2.0
• [fixed] potential stack overflow in underlying UDP channel
• [fixed] Message ID conflict
• [fixed] incomplete cleanup when reregister a observation
• [fixed] race condition when cancelling retransmission
• [fixed] for parentless resources
• [fixed] RTT for blockwise transfers
• [fixed] success range for code constants