Add alter column capability for html5 websql

 Add alter column capability for html5 websql,  please  config the persistence.version and persistence.alterColumnQueries in your code, For example:
`persistence.version = 2.0;
 persistence.queries = ['ALTER TABLE User ADD COLUMN address TEXT'];`

 If you have column change in your code, just change the persistence.version = 2.0 ,and add your alter sql in persistence.queries , while you can not delete the column. Good luck.