Version 0.2.0

This version makes ijq's commandline interface more closely match that
of jq.

Some exmaples:

Specify an initial filter on the command line:

    $ ijq '.[] | .foo' data.json

If only a single argument is given then it is assumed to be a filter if
data is present on stdin; otherwise, it is interpreted as an input file:

    $ cat data.json | ijq '.[] | .foo'

    $ ijq data.json

Filters can still be specified from a separate file:

    $ ijq -f filter.jq data.json

When using the `-f` flag, all positional arguments are assumed to be
input files.