Add accessibility attributes

Including `<title>` to `<a>`
Add `aria-labelledby="search_box"` to input text
Change the css rule to `.entry-meta { color: #413E38;}`
Change the css rule to `.entry-footer{ color: #413E38;}`
I change the color because the audit accessibility developer tool  validate the website and show this color error: 
https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#-ax_color_01--text-elements-should-have-a-reasonable-contrast-ratio
The color is very similar to the previous one:
![antesletra](https://cloud.githubusercontent.com/assets/833998/4032204/c759357a-2c6d-11e4-8031-64934322a4f2.png)

![despuesletra](https://cloud.githubusercontent.com/assets/833998/4032220/ec876b0a-2c6d-11e4-8c78-9e30b1142c84.png)