This change affects the DatagramSocket and StreamingSocket classes.

Status codes are already filtered in curlHeaderCallback, so there's no
need to remove them again in parseHttpHeaders. Request headers will
never include a status, so there's no need to remove the status in that
case.

This commit removes the various compiler-specific JUCE_DEPRECATED macros and replaces them with C++14's deprecated attribute. It also removes the JUCE_CATCH_DEPRECATED_CODE_MISUSE flag as we can rely on the override specifier catching usage of these old virtual methods, and tidies up the DOXYGEN preprocessor checks as they were inconsistent across the codebase.

This fixes warnings that are emitted when building with the `-analyze`
flag enabled.

- Added a new URL::createInputStream() overload that takes an InputStreamOptions helper class to simplify stream creation.
  - Modified the internals of URL and WebInputStream so that parameters are only added to the request body when ParameterHandling is set to inPostData. This allows POST data to be added via URL::withPOSTData() and sent with URL-encoded parameters.