Implemented Email Dialog

IMPORTANT NOTE: 
    This must be tested on device and the device needs to have at least one email account setup. If on simulator, it will not open the email dialog.

Properties currently working:

- toRecipients - [ string array ]
- ccRecipients - [string array ]
- messageBody - string
- subject - string

Properties implemented but not working:
- bccRecipients - [string array]
- html - boolean

Methods working
- open

Methods implemented but not working
- addAttachment (missing Ti.Filesystem)

Sample code

```
var win = Titanium.UI.createWindow({});

var btn = Ti.UI.createButton({
	title: 'open'
});

win.add(btn);

btn.addEventListener('click', function(){
	var email = Ti.UI.createEmailDialog({
		toRecipients: ['email@domain.com', 'email@domain.com'],
		ccRecipients: ['email@domain.com'],
		bccRecipients: ['email@domain.com'],
		messageBody: 'This is the message body',
		subject: 'this is a title',
		html: true
	});
	email.open();
});

win.open();
```