remove 3 build flags

* Removed the webapp-secure build flag, rolling it into the webapp build
  flag.
* Removed the quvi and tahoe build flags, which only adds aeson to
  the core dependencies.
* Removed the feed build flag, which only adds feed to the core
  dependencies.

Build flags have cost in both code complexity and also make Setup configure
have to work harder to find a usable set of build flags when some
dependencies are missing.

Remote/Web.hs

@@ -5,8 +5,6 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-{-# LANGUAGE CPP #-}
-
 module Remote.Web (remote, getWebUrls) where
 
 import Annex.Common
@@ -20,10 +18,8 @@ import Logs.Web
 import Annex.UUID
 import Utility.Metered
 import qualified Annex.Url as Url
-#ifdef WITH_QUVI
 import Annex.Quvi
 import qualified Utility.Quvi as Quvi
-#endif
 
 remote :: RemoteType
 remote = RemoteType {
@@ -82,13 +78,8 @@ downloadKey key _af dest p = unVerified $ get =<< getWebUrls key
 			let (u', downloader) = getDownloader u
 			case downloader of
 				QuviDownloader -> do
-#ifdef WITH_QUVI
 					flip (downloadUrl key p) dest
 						=<< withQuviOptions Quvi.queryLinks [Quvi.httponly, Quvi.quiet] u'
-#else
-					warning "quvi support needed for this url"
-					return False
-#endif
 				_ -> downloadUrl key p [u'] dest
 
 downloadKeyCheap :: Key -> AssociatedFile -> FilePath -> Annex Bool
@@ -116,11 +107,7 @@ checkKey' key us = firsthit us (Right False) $ \u -> do
 	showChecking u'
 	case downloader of
 		QuviDownloader ->
-#ifdef WITH_QUVI
 			Right <$> withQuviOptions Quvi.check [Quvi.httponly, Quvi.quiet] u'
-#else
-			return $ Left "quvi support needed for this url"
-#endif
 		_ -> do
 			Url.withUrlOptions $ catchMsgIO .
 				Url.checkBoth u' (keySize key)