* add .clang-format for automated code formatting
* automatic code formatting
* move config.mk below all target to allow custom non-default build targets
* add license to the top of the file
* use correct header file guards syntax
* convert to single-header, header-only library
* update makefile to use jsmn as a header-only library
* update readme
* add changed from PR #143
* fix clang warnings
* add changes from PR #142
* add consts as per PR #134