Fix harmless compiler warnings for MSVC in the showdb/showwal command line tools.
Fix warnings caused by the previous commit.
Fix warnings related to having a 64-bit size_t.
Fix some harmess compiler warnings in the FTS3 Unicode module.
Fix harmless compiler warnings in the showdb and showwal tools and in
the unicode tokenizer of FTS3.
Update the sqlite3_stmt_busy() function so that it correctly returns true for "ROLLBACK" statements that have been stepped but not yet reset.