Binary: add expected trigger.

- Add expected trigger "decimal 3 to binary" which fixes #291
- Add complementary trigger for 'hex' where it may be ambiguous.
- Normalize hex conversion output.
- Add additional prepositions which imply conversion ('as', 'into')
- Adjust output style to be more like other IAs.
- Improve comments, albeit very slightly.
- Add additional tests, including covering all example queries.
- Add ABSTRACT to reduce scroll spam under `dzil test`
Merge branch 'master' into binconv

Conflicts:
	t/Binary.t
Binary: tighten up the binary to decimal trigger.

- Do not match when there are non-binary [01] characters in something
  which we posit to be "binary."
- Add test cases for the regressions.

We don't want to match on things which do not appear to be asking for
conversions. In the binary -> decimal case this is somewhat more
ambiguous, except that we can demand that the input look like binary, so
it's actually not so bad.

I didn't pay enough attention to the previous regex and how it matched
up with the new code. :(
Merge pull request #322 from mwmiller/binconv

Binary: add expected trigger.