[tutorial] some introductory words about tags...
Merge branch 'tutorial' of https://github.com/jgrewe/nixpy into tutorial
[tutorial] introductory words about types and names
[tutorial] finished tag and multi-tag snippets
[tutorial] add feature descriptions
[tutorial] brief descriptions of the source concept
[tutorial] add conceptual description of the metadata
[tutorial] link correction, corrected code-blocks
Merge pull request #98 from jgrewe/tutorial

Aaawesome