* MemoryError is now raised instead of sqlite3.Warning when memory is not enough for encoding statement to UTF-8 in Connection.__call__() and Cursor.execute().
* UnicodEncodeError is now raised instead of sqlite3.Warning when statement contains surrogate characters in Connection.__call__() and Cursor.execute().
* TypeError is now raised instead of ValueError for non-string script in Cursor.execute().
* ValueError is now raised for script containing NUL instead of truncating it in Cursor.execute().
* Correctly handled exceptions raised when getting boolean value of the result of the progress handler to bool.

Also added many tests which cover different exceptional cases.