header escaping

[cg2v]

stomp 1.1 and 1.2 require that colon (:), backslash, and newline be backslash escaped in header values (stomp 1.2 also adds carriage return). stomp.py doesn't implement this, which leads to strange looking error headers from activemq:

User XXX is not authorized to read from\c queue\c//yyy

it may also prevent some servers from accepting passwords containing colons (thankfully, activemq is lenient about this)

[jasonrbriggs]

Fixed in the 4.0.11 release