Availability - use correct start and end times

In the Availability service ensure we are checking the correct start and
end times
Updated all NuGet packages except StructureMap.
Corrected missing mandrill reference.
Added etag caching to the lol handler
Merge pull request #3859 from purplebricks/Packages_Update_Manhattan

Updated all NuGet packages except StructureMap.
Merge pull request #3860 from purplebricks/Lol-ETAG

Added etag caching to the lol handler
Merge pull request #3808 from purplebricks/FB1761-ValuationMultipleBookings

Availability - use correct start and end times