Release 0.161.0

The jsoncons::jsonpath extension has been rewritten, see JSONPath extension revisited.

Enhancements to JSONPath extension

• Added a new function make_expression for creating a compiled JSONPath expression for later evaluation.
• The json_query and json_replace functions now take an optional result_options parameter that allows duplicate values (i.e. values with
  the same node paths) to be excluded from results, and for results to be sorted in path order.

Changes to json_query

• The parameter result_type has been replaced by a bitmask type result_options.
  For backwards compatability, result_type has been typedefed to result_options,
  and the value and path enumerators are still there. In addition, result_options
  provides options for excluding duplicates from results, and for results to be sorted in
  path order.

• Until 0.161.0, json_query was limited to returning an array of results, a copy.
  With 0.161, json_query allows the user to provide a binary callback
  that is passed two arguments - the path of the item and a const reference to the
  original item.

• Until 0.161.0, json_replace allowed the user to provide a unary callback to replace
  an item in the original JSON with a returned value. This overload is still there, but has
  been deprecated. With 0.161, json_replace allows the user to provide a binary callback
  that is passed two arguments - the path of the item and a mutable reference to the
  original item.

Changes to supported JSONPath syntax

• Previous versions allowed optionally omitting the '$' representing the root of the
  JSON instance in path selectors. This is no longer allowed. In 0.161.0, all path
  selectors must start with either '$', if relative to the root of the JSON instance,
  or '@', if relative to the current node. E.g. store.book.0 is not allowed,
  rather, $store.book.0.
• Previous versions supported union of completely separate paths, e.g.
  $..[name.first,address.city]. 0.161.0 does too, but requires that the
  relative paths name.first and address.city start with a '@', so the
  example becomes $..[@.name.first,@.address.city] .
• Previous versions supported unquoted names with the square bracket notation,
  this is no longer allowed. E.g. $[books] is not allowed, rather $['books']
  or $["books"].
• Previous versions allowed an empty string to be passed as a path argument
  to json_query. This is no longer allowed, a syntax error will be raised.
• In 0.161.0, unquoted names in the dot notation are restricted to digits 0-9,
  letters A-Z and a-z, the underscore character _, and unicode coded characters
  that are non-ascii. All others names must be enclosed with single or double quotes.
  In particular, names with hypens (-) must be enclosed with single or double quotes.

Enhancements to JMESPath extension

• Function arity errors are now raised during compilation of the JMESPath expression
  rather than during evaluation.