Holiday request2

Been messing around with the holiday app the last couple of days and  made a few changes. The first one here is editing the holiday request email. The email will now tell the manager receiving what other users have holiday that clash with the dates that you have requested. 

This is shown in the attached image

![_guerrilla_mail_-_disposable_temporary_e-mail_address](https://f.cloud.github.com/assets/5382335/1270240/c9779e26-2d06-11e3-87de-fd1cca2524a0.png)

The code may not be as efficient as possible but I was just playing about