Add options parameter to customize encoding

Merge pull request #20 from jdecool/readme-badge

Add CI badge in the README

Fix memory leak on objects with integer keys

Merge pull request #14 from hotrush/fix-int_keys

Fix memory leak for objects with numeric keys

Update PHP version requirements

0.4.0

Update PHP versions a bit

0.3.1: Merge pull request #6 from Lisio/master

Fixed escaped string parsing