Assorted changes in documentation

Use Math.log10() and remove Mode.getOracle()

Remove Mode.supportOffsetFetch

Show information about office configuration instead of fallback PDF generation mode

Describe datetime fields in documentation

Parse and treat fractional seconds precision as described in SQL standard

Add RESTRICT and CASCADE to DROP SCHEMA

Fix time overflow in DATEADD

Implement TABLE_CONSTRAINTS and REFERENTIAL_CONSTRAINTS from the SQL standard

Parse constraints in ALTER TABLE ADD [ COLUMN ]