This change also drops the principle that fields with the same keys would be
grouped together. This was initially inspired by Boost::Beast, but it means a
lot of extra copying of data when adding/organizing the list, as well as
inefficient querying on each add. Now that the design choice is to fully go
for the raw string as underlying data storage, that choice is not necessary.
In the future it may be able to emulate the grouping or retrieving of lists
of values in the API, rather than as a fundamental principle of the data
storage.
Change-Id: I2667cfa38eb3b7b75393ee71fb038231a40b4193
Niels Sascha Reedijk
8ccf8fb44d