Add missing space after "Serialized" in StorageLevel

Current code creates outputs like:

scala> res0.getStorageLevel.description
res2: String = Serialized1x Replicated
Typo: applicaton
Merge pull request #226 from ash211/patch-4

Typo: applicaton
Fix small bug in web UI and minor clean-up.

There was a bug where sorting order didn't work correctly for write time metrics.

I also cleaned up some earlier code that fixed the same issue for read and
write bytes.
Merge pull request #225 from ash211/patch-3

Add missing space after "Serialized" in StorageLevel

Current code creates outputs like:

scala> res0.getStorageLevel.description
res2: String = Serialized1x Replicated
Merge pull request #227 from pwendell/master

Fix small bug in web UI and minor clean-up.

There was a bug where sorting order didn't work correctly for write time metrics.

I also cleaned up some earlier code that fixed the same issue for read and
write bytes.