Clarified aspects of smart property creation; other cleanup
added "go live" block number for DEx
Fix issuer share calculation error, clarify tx 22 behavior
Fixed typos, errors; clarified ecosystem & replace/append

Still some questions pending, see issues #102, #103, #104.
more clarity on replacing/appending SPs, currency id values
Merge pull request #97 from marv-engine/smart_prop_fixes

Merge now, cleanup more later if needed :)