Add space between numbers and units in README, package documentation.

When we added space between numbers and units in 64dbdae0d393b7d71480a6dace78456396b55286,
the README and package documentation weren't updated. This fixes that.

Also fix various other minor issues in documentation that I found.
Use single space between sentences in README, to follow Go style.

Follows 64dbdae0d393b7d71480a6dace78456396b55286.
Helps #21.
5 files changed