[WIP] First layout of the Files Session implementation.
[WIP] Enqueuing of the different operations.
- Built many tests for the Session object.
Merge branch 'master' into new-files-api

Conflicts:
	Raven.Studio.Html5/Content/app.css
[WIP] RegisterUpload with Streams.
Merge branch 'new-files-api' of https://github.com/Corvalius/ravendb into new-files-api
- Deferred action copies data by blocks instead of allocating all the data in memory.
Merge branch 'new-files-api' of https://github.com/Corvalius/ravendb into new-files-api
Addding a new test for FileSession using listener
- Moved the Session Listeners tests to its own file.
- Fixed: If we preallocate more space but then upload less, we will report back the correct size for download.
Merge branch 'master' into new-files-api
- When the reported size of the file is not the size sent over the wire, we fail on the save changes.
Merge branch 'master' into new-files-api

Conflicts:
	Raven.Studio.Html5/Content/app.css
- LoadFileAsync implementation.
- Basic checks for AsyncFilesSession.
- Renamed some methods in the IAsyncFilesCommands.
Merge branch 'new-files-api' of https://github.com/Corvalius/ravendb into new-files-api

Conflicts:
	Raven.Studio.Html5/Content/app.css
Fixing potential bug in AsyncFilesSession.
Matching FileHeader and FileHeaderInformation object structure.
RavenDB-2347 Finish document's conflicts page
Merge branch 'RavenDB-1963' into RavenDB-1441
New files/metadata endpoint to retrieve file headers for a given list of files