Switched plain text +/- buttons with glyphicons plus/remove. Removed wor...

...d 'add' from some of the buttons so that they all look the same

Before
![old](https://cloud.githubusercontent.com/assets/568286/4155566/7f9ad076-346b-11e4-9d76-09c928ba5a0a.png)


After
![new](https://cloud.githubusercontent.com/assets/568286/4155567/83863c20-346b-11e4-9c51-2bdf3f48cf8f.png)


@jcoyne I removed it but I had to add an empty string as the text. Otherwise Rails does a weird double HTML encode of the text.