WARNING: Tried to load angular more than once.

Solved removing require('angular')
```js
module.exports = factory(require('angular'), require('pikaday'));
```
to
```js
module.exports = factory(require('pikaday'));
```
*apply changes for all UMD exports*
___
and changing **factory** params
```js
function (angular, Pikaday) { ... }
```
to 
```js
function (Pikaday) { ... }
```