1) More testing

2) An even higher level function for execution of queries in a more
   convenient way.  It should handle busy queries and expired statements
   automatically.

3) TODO: Add the following wrappers:

  a) Better SQL Function support (aggregating ones)
  b) Collation support
  c) Authorization support
  d) Trace/profile support
  e) progress handler support
  f) commit hook support
  g) global_recover, get_autocommit, db_handle, temp_directory
  h) encryption support (not in SQLite anyway)
