5.6.0

• Implemented a snprintf to [hopefully] stop recursion. Thanks to drok.
• Added append_string and friends for better string output.
• Fixed strndup handling when it is a macro. Thanks to danielgora.
• Fixed strndup configuration and handling in general.
• Added better getenv handling.
• Fixed issues around page-size detection and heap extension.
• Added circleci to github.
• Improved the test program output.
• Added strnlen configuration and handling.
• Moved to git on April 9, 2018.