Command line improvements, filtered Get option

This release features two command line improvements, the "get" verb now will accept a field name (e.g. type, who, what, when, where) and I added a -values option to return just the value without the namaste prefix, one value per line.

     namaste get who
     namaste -values get who
     namaste -json get who
     namaste -json -values get who

Yields:

    # get who
    namastes: 1=Doiel,R.S.
    # -values get who
    Doiel,R.S.
    # -json get who
    ["1=Doiel,R.S."]
    # -json -values get who
    ["Doiel,R.S."]

In the Go package the "Get" function now takes an array of strings which you can use to filter the Get results.
The strings can be in the form of "0", "1", "2", ... or "type", "who", "what", ...