apt-iselect: Add package browsing to Debian apt-get

Run apt-iselect searchterm, and then you'll be prompted with a menu of packages that match the term. Assuming there are packages that match the search term, you can scroll through the results one at a time using your arrow keys, page through results using the "Page Up" and "Page Down" keys, or use "g" to skip to the first line and "G" to skip to the last. Using "q" will allow you to quit without selecting any packages, "h" will give you a help page for iselect, which is used to display the results.

Hit "enter" to read the description of any packages that look interesting. If you want to install that package, all you need to do is select the package name and hit "enter" again to install it — from that point, it's basically as if you had just typed "apt-get install packagename."