Configurable HTTP request parameters - max request length, max header size, chunk size

Add ability to override default HTTP request details:
- request line length - default 4096
- header size - default 8192
- chunk size - default 8192

Add use of system properties:
- http.netty.maxInitialLineLength
- http.netty.maxHeaderSize
- http.netty.maxChunkSize
(each to be defined as int value in bytes)

These values are passed in to constructor for org.jboss.netty.handler.codec.http.HttpRequestDecoder
If the system properties are not defined, the current default value is used,