Better API description in README.md

[brody4hire]

I found a nice sample of the basics at: https://gist.github.com/andyj/1599544

UPDATE other items:

• link to this from README.md
• document this to be partially compliant to the Web SQL API for asynchronous operations only
• recommend cordova-plugin-console for logging (!!)
• clearly document how to log res object (JSON.stringify(res) is not recommended)
• tips-and-tricks section~~/document~~ (basic)
• More detailed Web SQL API compliance level
• more extensive tips-and-tricks section or document
• multi-page apps should define Content-Security-Policy on all pages
• memory usage on iOS increases to a certain point before built-in Objective-C ARC cleans it up, see: Memory Issue litehelpers/cordova-sqlite-evplus-ext-legacy-build-free#1

GENERAL: make it as easy and simple as possible for someone getting started with sql