1. Never allocate empty statement - always use att->prepare() to create statement interface
2. Separated IStatement into 2 parts - statement itself and resultset.
3. Added stmt->openCursor() (and att->openCursor() for unprepared statements) to create IResultSet.
4. Always use IMessageMetadata (former IParametersMetadata) to pass message fromat info from client,
therefore avoiding need in BLR generation in client applications.
1. Frontported fix for CORE-3935 and CORE-3993.
2. Added debugging support for mutexes and rwlocks in Vulcan style.
Unfortunately after last 'svn up' build asserts in JrdStatement:71.
Also some cleanups, the most important are:
- meaningful ctor on Jrd::Lock, helping to avoid code dup
- avoid unneeded h-file dependencies, making boot build engine dependent
2. Avoid massive segfaults when closing heavily loaded server.
3. Restored logic in YValve required for correct shutdown.
4. Do not change externally visible request body when preparing it.
