Log Message:
Update to 0.13.9

CHANGES.txt:
0.13.9
    #50, fix a space leak
    #36, fix the demo examples
    #35, make IsString a superclass of StringLike
    #33, make flattenTree O(n) instead of O(n^2)
0.13.8
    #30, add parse/render functions directly to the Tree module
0.13.7
    #32, make sure upper case &#X works in lookupEntity
0.13.6
    #28, some named entities require a trailing semicolon (e.g. mid)
0.13.5
    #26, rename the test program to test-tagsoup
0.13.4
    #24, add isTagComment function
    Update the copyright year
0.13.3
    Work on GHC 7.9
0.13.2
    Remove all package upper bounds
    Allow QuickCheck-2.6