Add «OR» operator

[jpbecotte]

A query can accepts many operands, like the following example:

var queryString = JSON.stringify({
  table: 'book',
  query: [
    	[ 'title', 'match', '^Harry Potter.*' ],
        [ 'price', 'lt', 15.30 ]
    ]
});
ds.record.getList( 'search?' + queryString );

But each opererand is executed like if they where seperated by a «AND» operator.

In SQL, this would results in the following WHERE clause: title LIKE 'Harry Potter%' AND price < 15.30.

I would like to be able to combine two operands with an «OR» operator. Something like ['or', ['title', 'eq', 'A title'], ['price', 'lt', 15.30]]would mean : Give me the list of all books that have 'A title' or that the price is less than 15.30.