Remove recursion in LinkParser

[emgre]

It is currently possible to wind up the stack by sending 0x07 0xAA 0x07 0xAA ... to the LinkParser. The recursion on LinkParser::parse_many (called through LinkParser::parse_header) should be flatten out.

The issue is mitigated by the buffer size of the sent data, but the recursion should still be removed.

[emgre]

Also, perhaps a re-synchronization should also happen on a failed CRC check in the body. It could prevent losing a valid overlapped frame (which could happen quite easily). However, this re-synchronization should not be recursive (as suggested in this issue).