SFI Response: Orientation can be "Unknown"

Also, replaced "Panoramic" with "Panoramichorizontal" and "Panoramicvertical" from the Request section. "Panoramic" may need to be added back if that's also still valid.
Fashion Phrases -> FashionPhrase; +EditorialSegment.Invalid
Merge pull request #12 from ryanthecubfan/master

Added GetAllProductOfferings
Merge pull request #11 from Grumpicus/patch-3

Fashion Phrases -> FashionPhrase; +EditorialSegment.Invalid
Merge pull request #10 from Grumpicus/patch-2

SFI Response: Orientation can be "Unknown"
PanoramicHorizontal and PanoramicVertical orientations added.
PanoramicHorizontal and PanoramicVertical orientations added.
Update SearchForVideos.md

Noted that we do not have non-watermarked comp videos at this time.
Update SearchForVideos.md
Update SearchForVideos.md
Documenting 90 ImageId limit in GetImageDetails
Adding DownloadsRemaining response parameter to GetImageDownloadAuthorizations.
Removed duplicate field entry, updated details
Merge pull request #13 from jphillips-gettyimages/master

Removed duplicate SizesDownloadableImages field entry, updated details.
Added FailedToGetDownloadUrl to _DownloadUrl_.Status
Update GetImageDownloadAuthorizations.md

Updated descriptions for result fields.
Update GetImageDownloadAuthorizations.md

Further updates to response fields.
Update AvailableRefinements.md

Updated the list to reflect all possible categories for RefinementOptions that can be found in the SearchForImages response.
Update AvailableRefinements.md

Alphabetized the list.
Update AvailableRefinements.md

Grammar/formatting clean up.