Filter sections, Check all local volumes

Hello,

I'm hoping you can integrate the following changes into PleXBMC, as I think they (or at least one of them) will be helpful to folks.  I don't pretend to know anything about developing XBMC addons, so these is just quick-n-dirty changes that make life much easier for me.

First - A filter for Media Sections.  Added a simple filter string in the settings, and a check before adding a new section to see if the address, server name, or share name are in the filter string. If it is, the section isn't added. I have a rather complicated setup at home with multiple PMS boxes, and I cannot, for the life of me, completely isolate them.  It's easier to just filter out the box I don't want, and, at the same time, this seems like a useful feature in general... so, that's that.

Second - I have tons of DVD images and a central server sharing several volumes to various media devices (this server also runs the PMS instance that PleXBMC talks to).  Since I need a real mount to use the DVD images, it seemed to me that rather than trying to get all my mount points to match the server exactly, I could just test all the local drives on the Windows box to see if I see a file. Kinda brute force, but it means that rather than worrying about streaming, or caring if things match up directly, I share the drives, mount them on the PleXBMC box, and it finds the files.  This REALLY simplified things for me.  I'm only testing a-z, but it's 2-3 lines of code that seem like they could make life easier for people running PleXBMC on windows.  Added a checkbox to enable/disable in the Playback section settings.

Lastly - I'm consistently getting a script error on PrintDebug (unicode to ascii error). I tried using encode('ascii', 'ignore'), but didn't have much luck, and didn't care that much... so I just stuck that in a try/except block.  I don't really consider that to be an acceptable solution, but I just wanted the thing to run.

Anyway, these changes seem to work. They aren't very intrusive, and I think they add some value to application, so I'm sending this request :)

Best wishes,
John