(fix) compiler handles incorrect open tags

- Modified compiler to handle incorrect open tags as text:
![image](https://cloud.githubusercontent.com/assets/2935356/4446535/46e12126-4803-11e4-97e7-7eb78e2d0508.png)
If a closing tag is found, a matching opening tag needs to be present in order to proceed.

- Added tests for cases in which the compiler should output correct tags