Add case guideline for SQL key words, identifiers

The intent of uppercasing SQL key words and lowercasing SQL identifiers
is to distinguish them from each other, separating SQL names from the
domain names (table and column names).

http://www.postgresql.org/docs/9.2/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS

Also, fix alphabetical sorting of 'Formatting' section.