This behaves a lot like jassert, but will never emit unused-variable
warnings.

See BREAKING-CHANGES.txt for more details.

The previously used getUserDefaultUILanguage() was based on the deprecated
LCID/LANGID concept. It had an increasing number of corner cases as not
every locale had associated LCIDs. The new solution is based on locale
names (string based) and will return reasonable names in more situations.

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

When passing in valid data with zero size, replaceWith() will do nothing and leave the MemoryBlock in its previous state which may be unexpected. replaceAll() will reset the MemoryBlock and resize it to 0

This ensures the function IUnknown_GetWindow is declared in shlwapi.h
when building against the Windows 7 SDK.

- 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.