Added the ability to change uploaded-picture position

**I just found a old patch which I want to re-apply on sechat.org. Maybe someone else want it in the official branch..**

You're now able to move your uploaded picture(s) with a simple syntax:

* select in your status message one or multiple pictures
* add to the status message two square brackets with the picture number e.g. [1]
* If you have multiple pictures you have to increase the number

The order how you select the pictures matters:

Iam_the_first_one.png         -> [1]
now_the_second_picture.jpg    -> [2]
what_number_could_that_be.png -> [3]

![modifiy_uploaded_picture_pos_feature](https://cloud.githubusercontent.com/assets/652428/3340991/11f3332e-f884-11e3-9e90-506a48cab338.png)