Windows Phone 8.1 Support
Merge branch 'windows-phone-8.1'
added release note entry for Windows Phone 8.1 PR
only return 'tomorrow' if datetime is actually tomorrow

Fixes issue #254
added release note for fixing DateTime.Humanize for tomorrow
Merge branch 'fix-humanize-datetime-for-tomorrow'
releasing v1.28.0
oops - added the missing release header
Fixed the inlined contributors!
Clarified what is treated as an acronym.
Acronym notes

Additional examples of strings treated as acronyms, with workaround using Transform() method.
Merge pull request #316 from iadaz/patch-1

Clarified what is treated as an acronym.