Misc nitpick fixes for v2.1

[nickbp]

1. Some fixes for license.md:
   • The version was 2.l, not 2.1.
   • Remove trailing spaces from some lines.
   • Some spaces were 0xC2 0xA0, or UTF8 non-breaking space, rather than regular ASCII spaces (0x20). I originally found the issue via my editor, emacs, displaying the spaces with an underscore, then diagnosed the content of the weird spaces using echo "linehere" | hexdump -C.
2. Updates misc parts of the site content that currently reference 2.0 to instead reference 2.1 (found via grep)

Some open questions:

• The root repo LICENSE.md is still 2.0. Left it as is since I didn't know whether it was desirable to change it yet.
• I updated the FAQ to mention "2.0 and later" for outside help but I don't know if that's actually accurate. Feel free to correct that.