Revisit error styles

Error styles, which are similar to those for Individual Electoral Registration.

Opinions, please. 

**Mobile:**

**1. Where the border on the left hand side connects both the field with the error and the error message.**

![errors-mobile](https://cloud.githubusercontent.com/assets/417754/3341446/782ef584-f888-11e3-9473-2c1594dd2675.png)

**2. Where there is a space underneath the border on the left hand side and the error message.**

![errors-with-spaces-mobile](https://cloud.githubusercontent.com/assets/417754/3341459/9cf7a5dc-f888-11e3-8a09-f36af5e5ee11.png)

**3. For longer forms, a summary box is provided at the top of the page with jump links.**

![errors-with-summary-mobike](https://cloud.githubusercontent.com/assets/417754/3341465/a8a53ad4-f888-11e3-8ca1-0025bbaa7b6b.png)

**Desktop:**

**1. Where the border on the left hand side connects both the field with the error and the error message.**

![errors-desktop](https://cloud.githubusercontent.com/assets/417754/3341439/6c20b6c4-f888-11e3-8ba6-0204d1d11988.png)

**2. Where there is a space underneath the border on the left hand side and the error message.**

![errors-with-spaces](https://cloud.githubusercontent.com/assets/417754/3341453/8a212870-f888-11e3-9ed0-414b9b60e0db.png)


**3. For longer forms, a summary box is provided at the top of the page with jump links.**

![errors-with-summary](https://cloud.githubusercontent.com/assets/417754/3341463/a5b7c198-f888-11e3-91c2-7e94098963ae.png)