Refactored NET request implementation.
- fixed potential issue with header conflict.
- simplified, and extract parts of the code into routine.
- Implemented read of chunked Transfer-Encoding
- Fixed potential issue with socket handling.
First steps to be able to exclude net or libcurl implementation when using http_client lib.
Removed from NET implementation the hack related to PUT and upload data (it was used to workaround an issue with libcurl).
