Add local + core commit SHAs to version string

[weefuzzy]

This uses git log to retrieve abbreviated SHAs for flucoma-core and the project being built, and appends them to the version string.

I've used the semantic versioning guidelines for including build meta data

Build metadata MAY be denoted by appending a plus sign and a series of dot separated identifiers immediately following the patch or pre-release version. Identifiers MUST comprise only ASCII alphanumerics and hyphens [0-9A-Za-z-]. Identifiers MUST NOT be empty. Build metadata MUST be ignored when determining version precedence. Thus two versions that differ only in the build metadata, have the same precedence. Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85, 1.0.0+21AF26D3—-117B344092BD.

[jamesb93]

This is gorgeous work:

Thanks for sorting this business out.