Minor improvements and bugfixes

Added: OracleSqlParser - support for COMMIT statement, i. e., COMMIT
COMMENT 'In-doubt transaction Code 36, Call (415) 555-2637' WRITE NOWAIT
or COMMIT FORCE '22.57.53', 1234
Improvement: Editor - when left parenthesis entered and there is not
immediate following character a closing parenthesis is automatically
inserted
Improvement: Snippet suggestion - snippets can be now suggested within a
statement if applicable
Added: OracleStatementSemanticModel - resolving column references of
join conditions