Escaping, appending operations, bug fixing

• Made jsonpatch more Elixir-API-like by adding Jsonpatch.apply_patch! (which raise an exception) and changed Jsonpatch.apply_patch to return a tuple.
• Implemented escaping for '~' and '/'
• Allow usage of '-' for Add and Copy operation
• Fixed adding and copying values to array
• Improved error feedback of test operation
• Fixed: Replace operation adds error to target
• Cleaned code: Replaced strange constructs of Enum.with_index with Enum.fetch

Improved documentation

Improvement of documents (especially for hexdocs.pm)

Reviewed documentation and code

The tests were improved since last release. The documentation was also reviewed.

Error feedback

Jsonpatch provides now helpful feedback on patch error like:

iex> patch = [
...> %Jsonpatch.Operation.Add{path: "/age", value: 33},
...> %Jsonpatch.Operation.Test{path: "/name", value: "Alice"}
...> ]
iex> target = %{"name" => "Bob", "married" => false, "hobbies" => ["Sport", "Elixir", "Football"], "home" => "Berlin"}
iex> Jsonpatch.apply_patch(patch, target)
{:error, :test_failed, "Expected value 'Alice' at '/name'"}

Better documentation

It were some documentation missing.

Feature complete

Jsonpatch should included every requirement of https://tools.ietf.org/html/rfc6902 at this point.