Create SPDX 2.1 conforming output

[jeremiah]

See title.

[jeremiah]

The SPDX 2.0 conformant output should be as an HTML page. So SPDXl runs over a directory and produces an HTML page with all the SPDX licensing information we can gather.

[jeremiah]

HTML page works. Now the page needs to include all the required SPDX 2.0 tags.