fix clojars url for org.flatland/useful
First try at explaining string operations.
Add (seq "foo").
Improve explanation of unicode caveat.
cl-format. (Move regular format next to it.)
More explanation on cl-format.
Improved explanations.
Extra explanation of format.
Instaparse examples.
Add instaparse to require's.
Introduce Instaparse.
Instaparse needs to be installed, so put instructions in the
context-free grammar section.
Implemented JSON as Instaparse example.
Added myself as contributor.
Fixed inconsistent naming.
Consolidate sections into main recipes area.
Briefer section introductions.
Clarify wording.
Improve Instparse section.
Add example of byte array.