Correct data extraction validator

Author: joaosimbiose

package.json

@@ -31,6 +31,5 @@
     "async": "^2.0.1",
     "sleep": "^4.0.0"
   },
-  "dependencies": {
-  }
+  "dependencies": {}
 }

src/slicer.js

@@ -193,7 +193,9 @@
                 // Check columns property, columns should have a maximum of 10 itens
                 if (key == "columns") {
                     if (value.constructor != Array) {
-                        throw new errors.InvalidQueryException("The key 'columns' in query has a invalid value.");
+                        if (value != 'all') {
+                            throw new errors.InvalidQueryException("The key 'columns' in query has a invalid value.");
+                        }
                     }
                     else {
                         if (value.length > 10) {