Merge pull request #4917 from jmarshallnz/rwarnings

Fix a bunch of warnings
[addons] adds OnEnabled/OnDisabled callbacks to save special-case stuff in CAddonDatabase

NOTE: still actually special-cased as combined add-ons could be disabled (e.g. service+plugin, where plugin
      is disabled should disable service as well).
[addons] adds GetRunningInstance() to CAddon, retrieving the running instance of the particular add-on, to remove special-casing from CAddonManager for PVR clients
[cosmetic] drop using namespace PVR from AddonManager
[addons] adds CanInstall() to CAddon to allow for non-install of add-ons by type rather than special-casing for PVR in CRepository
[addons] adds OnPreInstall/OnPostInstall callbacks for add-ons to remove addon type-specific code from CAddonInstaller
[addons] adds OnPreUnInstall/OnPostUnInstall to CAddon to get rid of addon type-specific code in CAddonInstaller
Ask the player which audio stream is played and store the selected audio index in CApplicationPlayer::SetAudioStream and nowhere else
Allow CStopWatch to be queried when stopped.
[view] fix label for default sort method in CGUIViewState

This adjusts the label which is used if no sort method is defined (Sort by: Name) to 'Name' as it's used in all CGUIViewState derivatives.

Also discussed at trac http://trac.xbmc.org/ticket/15045
Merge pull request #5140 from xhaggi/fix-default-sort-method-label

[view] fix label for default sort method in CGUIViewState
Refactor CStopWatch for inlinability.
Clean up ambiguous usages of CStopWatch.
Update CStopWatch::Stop test
videolibrary: by default sort movies inside a set by year and ascending
Merge pull request #5136 from Montellese/upnp_fix_devicename

UPnP: fix friendly name on non-Xbox clients
[win32] CCPUInfo: fix used long time average as current average, check result of GetSystemTimes(), unify win32 and non-win32 code.
musicdb: remove DeleteSong/DeleteArtist/DeleteAlbum which didn't have any implementation
[darwin] CPUInfo: fix iOS cpu model identification
upnp: serialize/deserialize datetime values in W3C format