Revert "Add mode"

src/redux/navigation.js

 const keyMirror = require('keymirror');
 
 const Types = keyMirror({
-    SET_MODE: null,
     SET_SEARCH_TERM: null
 });
 
@@ -10,8 +9,6 @@ module.exports.navigationReducer = (state, action) => {
         state = '';
     }
     switch (action.type) {
-    case Types.SET_MODE:
-        return action.mode;
     case Types.SET_SEARCH_TERM:
         return action.searchTerm;
     default:
@@ -19,11 +16,6 @@ module.exports.navigationReducer = (state, action) => {
     }
 };
 
-module.exports.setMode = mode => ({
-    type: Types.SET_MODE,
-    mode: mode
-});
-
 module.exports.setSearchTerm = searchTerm => ({
     type: Types.SET_SEARCH_TERM,
     searchTerm: searchTerm