vNext - drop obsolites

[mauroservienti]

Connected to #258
Depends on #257

Once #257 is merged, rebase on develop and retarget to develop.

[nazarenomanco]

@mauroservienti I should have found all the "#if": these are missing because I'm not sure of the correct action:

• AnalyticsServices (delete?)

#if !SILVERLIGHT && !NETFX_CORE
                this.Identity = Thread.CurrentPrincipal.Identity;
#endif

• Ensure: #if DEBUG (leave?)

Thanks!

[mauroservienti]

Thanks @nazarenomanco, merging.