Add support for tagged SQL queries

Tagged SQL queries are queries constructed via ES6 tagged template
strings. For instance, one can do:

```js
var result = sql`SELECT ${1} AS "var"`;
```

The `sql` tag can transform the template string so that it returns
something like:

```js
var result = { query: 'SELECT ? AS "var"', values: [1] };
```

This makes it ideal for writing elegant SQL by passing the tagged query,
containing the `query` and `values` properties to `sequelize.query`.

lib/sequelize.js

@@ -665,7 +665,6 @@ module.exports = (function() {
    */
   Sequelize.prototype.query = function(sql, callee, options, replacements) {
     var self = this;
-    sql = sql.trim();
     if (arguments.length === 4) {
       deprecated('passing raw query replacements as the 4th argument to sequelize.query is deprecated. Please use options.replacements instead');
       options.replacements = replacements;
@@ -682,6 +681,22 @@ module.exports = (function() {
       options = { raw: true };
     }
 
+    if (Utils._.isPlainObject(sql)) {
+      if (sql.hasOwnProperty('values')) {
+        if (options.hasOwnProperty('replacements')) {
+          throw new Error('Both `sql.values` and `options.replacements` cannot be set at the same time');
+        }
+
+        options.replacements = sql.values;
+      }
+
+      if (sql.hasOwnProperty('query')) {
+        sql = sql.query;
+      }
+    }
+
+    sql = sql.trim();
+
     if (!(callee instanceof Sequelize.Model)) {
       // When callee is not set, assume raw query
       options.raw = true;

test/integration/sequelize.test.js

@@ -308,6 +308,19 @@ describe(Support.getTestDialectTeaser('Sequelize'), function() {
       });
     });
 
+    it('throw an exception if `values` and `options.replacements` are both passed', function() {
+      var self = this;
+      expect(function() {
+        self.sequelize.query({ query: 'select ? as foo, ? as bar', values: [1, 2] }, null, { raw: true, replacements: [1, 2] });
+      }).to.throw(Error, 'Both `sql.values` and `options.replacements` cannot be set at the same time');
+    });
+
+    it('uses properties `query` and `values` if query is tagged', function() {
+      return this.sequelize.query({ query: 'select ? as foo, ? as bar', values: [1, 2] }, null, { type: this.sequelize.QueryTypes.SELECT }).success(function(result) {
+        expect(result).to.deep.equal([{ foo: 1, bar: 2 }]);
+      });
+    });
+
     it('dot separated attributes when doing a raw query without nest', function() {
       var tickChar = (dialect === 'postgres' || dialect === 'mssql') ? '"' : '`'
         , sql = 'select 1 as ' + Sequelize.Utils.addTicks('foo.bar.baz', tickChar);