Implementing download in AsyncFilesSession
 if we failed to connect, show the error message only once, for websockets
- if we failed to connect, show the error message only once.
- fix for unsupported browsers.
fix for server sending data with changes api every 5 seconds
Merge branch 'master' of https://github.com/ayende/ravendb into RavenDB-2480

Conflicts:
	Raven.Studio.Html5/App/common/changesApi.ts
	Raven.Studio.Html5/App/viewmodels/shell.ts
reconncet EventSource when connection drops
Fixed readme for optimized build
Implemented caching in LoadDirectoryAsync
Merge remote-tracking branch 'upstream/master'
[WIP] InMemoryFilesSession Operations.
RavenDB-2424 On client side index creation we should be able to inspect if an index is going to be refreshed.
Update readme.md
RavenDB-2488 Fixed .messageBox class after Durandal update
Update How to build.txt
RavenDB-2020 when collection count exceeds 15, the studio should color collections in gradient coloring
RavenDB-2391 security for databases/filesystems/counters should be unified
RavenDB-2435 Adding support for HTML stripping in indexing.
RavenDB-2471 Added column width sync from virtual table to column
selection dialog on documents page
- Removed the DirectoryHeader abstraction.
RavenDB-2484 Voron - BatchOperation.Value - avoid boxing / unboxing