Put default list width of some search criterias to auto

Some search combo box have by default to small size to be readable.

Extent to auto width those combo (category, catalog, organism..).

##### Before:
![widthauto1](https://f.cloud.github.com/assets/1491924/787861/918cd1b0-eaea-11e2-828e-b8824adbb58e.png)

##### Now:
![widthauto](https://f.cloud.github.com/assets/1491924/787860/8ca56bf8-eaea-11e2-8de8-c7c03df4986e.png)