rapidcsv

Added Get and Set operations with custom Converter definitions.

The GetCell, SetCell, GetColumn and SetColumn now take an
optional (last) parameter, specifying what Converter it should
use. This is a very handy way to override the default Converter, per
cell or column. One could now convert non-homogeneous data inside a
csv.

All interfaces, excluding the Document constructor, under certain
conditions, are backwards compatible, requiring almost no changes to
existing code.

The use of typeid(), for routing the conversions in the Converter
class, was removed and re-implemented, using template specialization.

Full examples of usage can be found in examples/ex008.cpp and the test
program, test063.

Removal of ConverterParams and its integration with Converter:

The fundamental problem with ConverterParams was that it only catered
for fixed and floating point type values. There was a default for each
of these. This was replaced with a single default value inside
Converter.

This change broke a part of the Document interface. The Document
constructor now takes a bool, instead of a ConverterParams
type. It is no longer possible to define default integer and floating
point values for a Document. However, a Converter with a supplied
default value can now be used to achieve this in a much more flexible
way, ie. per cell of per column.

This incompatibility should be a non-issue, as the use-cases
are probably limited. However, fixing existing code is trivial. See
the changes made to test048, as an example.

Also added an AUTHORS file, on request of @d99kris and added
formatting changes from running uncrustify on all the relevant source
files that were changed in this PR.