v0.15: Minor fixes and improvements

This release brings a few bugfixes and additions to the C++ API. A test framework has also been added with a basic test to start with. More to come!

What's Changed

• Use auto for basic types by @fire in #93
• Shorten the readme for readability by @fire in #96
• Apply code style in the readme by @fire in #99
• Add double builds by @Ughuuu in #101
• Add ClassDB::instantiate() and Node::create() by @fwsGonzo in #102
• Implement some global wrappers for C++ by @fwsGonzo in #103
• Use addr2line from Docker container, enable demangling by @fwsGonzo in #104
• Testing framework by @fwsGonzo in #106

Full Changelog: v0.14...v0.15