Fix MVSecondaryIndex.convertToKey() for ENUM data type

Ignore constant default values of columns in gathering of generated keys

Fix some compiler warnings and improve assert*() methods

Generate shorter queries in JdbcDatabaseMetaData.getTables() and remove some dead code

Fix more issues with range table and improve its documentation

# Conflicts:
#	h2/src/main/org/h2/engine/ConnectionInfo.java

Fix RangeTable.getRowCount() for non-default step

ValueBoolean constants are not cleared and may be used directly

code cleanups via IntelliJ IDEA inspections

Add remaining "time unit" management in "date_trunc"