disable open dropdown on input focused 

Changes:
- disable open dropdown menu on input get focused based on UX request, adjusting code and tests
- jslint minor fix

Before 
![untitled-old](https://f.cloud.github.com/assets/1945035/2290020/5c5608bc-a012-11e3-9375-b3be42c00a4c.gif)

After
![untitled](https://f.cloud.github.com/assets/1945035/2290023/63cdbf4a-a012-11e3-8968-750722d31e25.gif)