Fixes #124

Detect drives with names like xvd[a-z]+. Kernels with xvd driver support use
this convention, which is true in AWS for some platforms including RockStor.
Merge pull request #130 from schakrava/issue#124_xvd_drives

Fixes #124
Add close icon for appliances pop-up.
Merge pull request #131 from Mchakravartula/issue#123_close_icon

Add close icon for appliances pop-up.