Removed TODO and improved logging.
More tests for FastCGIProxyServlet.
Simplified/Improved handling of parser return values.
Only generating Status header if the response code is greater than zero.
Javadocs and comments.
Factored common code.
Always store HTTP fields to implement logic to detect the content mode.
Introduced parameter sendStatus200 to optionally send the Status
header when the response code is 200.
435223 - High cpu usage in FCGIHttpParser.parseContent(ResponseContentParser.java:314).

Since often FastCGI servers do not send the Status header if the
response is 200, the parser is now initialized with response code 200.
435338 - Incorrect handling of asynchronous content.

Return values from parser and parser callbacks must not be ignored.