suggestion for versioning
nimble currently appends the version number to the package name. 
I think it is better to start a new directory for every tag version.
The package directory can have a file specifying which version to use (by default).
if that file doesn't exist, assume the latest.
Add a command to nimble: `nimble set pkg 0.2.7-stable` or whatever the syntax is, to create that file.
Another option is to pass this info when compiling in a project-specific manner (information in the working folder)
a few ideas for consideration