Update SQLite to version 3.51.1 (sbooth#87)

Update SQLite to version 3.51.0 (sbooth#85)

SQLite 3.51 was released on 4 Nov.

Update SQLite to version 3.50.4 (sbooth#83)

Use `Testing` instead of `XCTest` (sbooth#82)

Update SQLite to version 3.50.2 (sbooth#79)

Add ENABLE_FTS4 package trait (sbooth#78)

Update README.md (sbooth#75)

Update SQLite to version 3.49.2 (sbooth#63)

Update SQLite to version 3.49.1 (sbooth#62)

Update SQLite to version 3.49.0 (sbooth#61)