Support TFTP options in RRQ and WRQ
Implement Option Acknowledge Message
Separate handlers for PUT and GET actions
Fix Option Acknowledge Message constructor arguments
Support TFTP options as defined in RFC 2347
Fix bug introduced in commit 13056b517c0b7d52fe63fd7a8685acca742481bf

https://github.com/cguimaraes/OpenTFTP/commit/13056b517c0b7d52fe63fd7a8685acca742481bf
Initialize TFTP options parameter in TFTP messages
Fix handlers in server session
Support TFTP OACK message in TFTP socket
Reset strBuilder in TFTP Options deserialization
Support blksize as defined in RFC 2348.
Merge branch 'options'