This rewrite fixes many problems that are very apparent in v1.

Problems fixed include:
- Inability to build without initializing git repository
- Inability to build when merging, rebasing, reverting, bisecting, cherry-picking, and being in detached head state
- Incorrect version calculation in some scenarios
- Inability to set alternate initial version
- Inability to build without an initial tag

Features added:
- Support for stages
- Support for specifying alternate development and main branch names
- Smart branching strategy inference
- Support for building with build metadata
- Zero config support (in most cases, there's no need to do anything but apply the plugin)
- Complete documentation to explain how to use the included and optional gradle properties