Escape quote marks in tags properly

Tags with double quote marks were not treated correctly. In both of the following images, the tag in question was this_"is"_a_test ..

Before this commit:
![before](https://cloud.githubusercontent.com/assets/2147649/3295751/ab353a04-f5c9-11e3-84cd-2f5412327afb.png)

After this commit:
![after](https://cloud.githubusercontent.com/assets/2147649/3295752/aeffb4e8-f5c9-11e3-8b6f-de3c25f61171.png)

The tag with double quote marks would still show in the list on the left and be searchable, it just wouldn't be easy to edit it.