Update csv-schema-grammar.ebnf

 Change IgnoreColumnNameCase TO IgnoreColumnNameCaseDirective for consistency
Update csv-schema-grammar.ebnf

correct wording around column directives (referred to as gobal directives in part of comment, number available wrong, and statement on order now misleading)
Update csv-schema-grammar.ebnf

Introduce new definition of ColumnRule as the righthand-side of ColumnDefinition, combining ColumnValidationExpr and ColumnDirectives
Update csv-schema-grammar.ebnf

Switch order of ColumnRule and QuotedColumnIdentifier
Update csv-schema-grammar.ebnf

Typo fix (had StarstWithExpr no StartsWithExpr)
Update csv-schema-grammar.ebnf

Formatting fix on UniqueExpr
Update csv-schema-grammar.ebnf

There were some Single Expressions listed in the body of the EBNF, not included in the definition of Single Expression