added separate constraint section
show only plain indexes, makeover for format constraints
updated format, and added primary key to index
assigned fixed names for constaints, UNIQUE indexes also mentioned under index
merge SytzeH: Add constraint names to \dt output

Merge pull request #99 from SytzeH/sql-layer-client-tools/constNmDt
https://github.com/FoundationDB/sql-layer-client-tools/pull/99