[doc] camel-http doc should mention that NTLM support is very limited.

The documentation of the camel-http component implies there is full support for NTLM.

However tests against IIS 8 prove this wrong.
Further from http://hc.apache.org/httpclient-3.x/authentication.html#NTLM

"NT Lan Manager (NTLM) authentication is a proprietary, closed challenge/response authentication protocol for Microsoft Windows. Only some details about NTLM protocol are available through reverse engineering. HttpClient provides limited support for what is known as NTLMv1, the early version of the NTLM protocol. HttpClient does not support NTLMv2 at all. "

These limitations on NTLM should be documented on the camel-http component doc.