Increase console font size

[As mentioned in #11501]

Before:
![editing__extras___modx_revolution](https://cloud.githubusercontent.com/assets/312944/3278467/2397550a-f3c1-11e3-9502-b3c26ecb0427.png)

Suggesting to change the font size to 13px, resulting in:
![editing__extras___modx_revolution](https://cloud.githubusercontent.com/assets/312944/3278483/f85dcdf0-f3c1-11e3-8041-09ce18001004.png)

Chose 13px because it was the font size used in the tree, as well as the navbar and everywhere the $baseText font is used.