Add SQLite build with unicode61 tokenizer and JNI

Use a custom build of SQLite 3.8.0.2 with FTS4 support and unicode61
tokenizer. SuggestionsProvider now uses it with the sqliteU61Query()
native method, instead of using the default SQLite library shipped with
Android that does not provide the unicode61 tokenizer.

The unicode61 tokenizer enhances unicode full-text searches and ignores
diacritics on latin characters.
gitignore: add obj/ and libs/
Use new SQLite DB built with FTS4 and unicode61