Installation and migration routine

[carstingaxion]

The current implementation of the plugin checks if something on the DB needs to be updated in a very expensive way, in terms of db hits. Within my tests it used multiple reads and writes to only do a typical version check, like many other plugins do it in a similar way. Even a object-caching plugin can - by design - not help, with the current implementation of the Migrate class.

A typical wp-admin request produces 8-11 db hits related to Embed Privacy, which is not cool.

Example

[carstingaxion]

epiphyt/embed-privacy#172