Specify and test level of W3 compliance

[brody4hire]

People have already identified issues where this SQLitePlugin was deviating from the W3 SQL API. I believe this plugin should be usable as a drop-in replacement for the version that is built-in for both the Android and iOS, providing some benefits such as predetermined location of database file, no synchronization issues, improvements for batch processing, and extensibility.

Someone pointed out an excellent link at http://html5doctor.com/introducing-web-sql-databases/ which describes the commonly-used SQL functions. The W3 spec is at http://www.w3.org/TR/webdatabase/ but it is already made obsolete so we should only support the most commonly used functions and fields.

The idea is to review these documents and find out if there are any missing features. From automatic testing (#4) a couple missing values were already confirmed for the Android version (#18). If there are any missing features, add the tests and fix them.