Update to 1.64

Upstream changes:
1.64 2019-08-12
    - Switched to a production version

1.63_05 2019-07-12
    - Upgraded SQLite to 3.29.0
    - Added sqlite_get_autocommit private method (GH#52)
    - Addded new db_config constants, notably to prohibit
      double-quoted string literals

1.63_04 2019-05-25
    - Upgraded SQLite to 3.28.0
    - Modified doc for sqlite_db_filename which actually returns undef
      or an empty string (GH#50)
    - Fixed ->quote($blob, SQL_BLOB) to quote correctly (GH#51, pali++)

1.63_03 2019-02-15
    - Applied a patch to fix segmentation fault on 32-bit big-endian
      platforms by Niko Tyni (GH#45)

1.63_02 2019-02-14
    - Upgraded SQLite to 3.27.1
    - Let a URI filename test skip if SQLite is compiled with URI filename
      support (GH#47)

1.63_01 2019-01-26
    - Made sure an internal hv is initialized (GH#45)
    - Fixed a number of tests to skip
    - Bumped up Test::More requirement
    - Replaced bundled Test::NoWarnings with Test::FailWarnings
    - Handle 'unknown' op in DBD::SQLite::VirtualTable::PerlData (Corion++)


(wen)