remove optimize subcommand; use --auto instead

get, drop: Added --auto option, which decides whether to get/drop content
as needed to work toward the configured numcopies.

The problem with bundling it up in optimize was that I then found I wanted
to run an optmize that did not drop files, only got them. Considered adding
a --only-get switch to it, but that seemed wrong. Instead, let's make
existing subcommands optionally smarter.

Note that the only actual difference between drop and drop --auto is that
the latter does not even try to drop a file if it knows of not enough
copies, and does not print any error messages about files it was unable to
drop.

It might be nice to make get avoid asking git for attributes when not in
auto mode. For now it always asks for attributes.

Command.hs

@@ -26,6 +26,9 @@ import qualified Git
 import qualified Git.LsFiles as LsFiles
 import Utility
 import Types.Key
+import Trust
+import LocationLog
+import Config
 
 {- A command runs in four stages.
  -
@@ -276,3 +279,19 @@ preserveOrder orig new = collect orig new
  -}
 runPreserveOrder :: ([FilePath] -> IO [FilePath]) -> [FilePath] -> IO [FilePath]
 runPreserveOrder a files = preserveOrder files <$> a files
+
+{- Used for commands that have an auto mode that checks the number of known
+ - copies of a key.
+ -
+ - In auto mode, first checks that the number of known
+ - copies of the key is > or < than the numcopies setting, before running
+ - the action. -}
+autoCopies :: Key -> (Int -> Int -> Bool) -> Maybe Int -> CommandStart -> CommandStart
+autoCopies key vs numcopiesattr a = do
+	auto <- Annex.getState Annex.auto
+	if auto
+		then do
+			needed <- getNumCopies numcopiesattr
+			(_, have) <- trustPartition UnTrusted =<< keyLocations key
+			if length have `vs` needed then a else stop
+		else a