Improvements of "gf -server" mode and related setup

"gf -server" mode now contains everything needed to run the minibar and
the grammar editor (including example-based grammar writing).

The Setup.hs script installs the required files where gf -server can find them.
These files have been moved to a new directory: src/www.

The separate server program pgf-http is now obsolete.

WebSetup.hs

@@ -0,0 +1,62 @@
+module WebSetup(installWeb,copyWeb) where
+
+import System.Directory(createDirectoryIfMissing,copyFile,removeFile)
+import System.FilePath((</>))
+import System.Cmd(system)
+import System.Exit(ExitCode(..))
+import Distribution.Simple.Setup(Flag(..),CopyDest(..),copyDest)
+import Distribution.Simple.LocalBuildInfo(datadir,buildDir,absoluteInstallDirs)
+
+{-
+   To test the GF web services, the minibar and the grammar editor, use
+   "cabal install" (or "runhaskell Setup.hs install") to install gf as usual.
+   Then start the server with the command "gf -server" and
+   open http://localhost:41296/minibar/minibar.html in your web browser
+   (Firefox, Safari, Opera or Chrome). The example grammars listed below will
+   be available in the minibar.
+-}
+
+example_grammars =  -- :: [(pgf, tmp, src)]
+   [("Foods.pgf","foods","contrib"</>"summerschool"</>"foods"</>"Foods???.gf"),
+    ("Letter.pgf","letter","examples"</>"letter"</>"Letter???.gf")]
+
+
+installWeb args flags pki lbi = setupWeb args dest pki lbi
+  where
+    dest = NoCopyDest
+
+copyWeb args flags pki lbi = setupWeb args dest pki lbi
+  where
+    dest = case copyDest flags of
+             NoFlag -> NoCopyDest
+             Flag d -> d
+
+setupWeb args dest pkg lbi =
+    do putStrLn "setupWeb"
+       mapM_ (createDirectoryIfMissing True) [grammars_dir,cloud_dir]
+       mapM_ build_pgf example_grammars
+  where
+    grammars_dir = www_dir </> "grammars"
+    cloud_dir = www_dir </> "tmp" -- hmm
+    www_dir = datadir (absoluteInstallDirs pkg lbi dest) </> "www"
+    gfo_dir = buildDir lbi </> "gfo"
+
+    build_pgf (pgf,tmp,src) =
+      do createDirectoryIfMissing True tmp_dir
+         execute cmd
+         copyFile pgf (grammars_dir</>pgf)
+         putStrLn (grammars_dir</>pgf)
+         removeFile pgf
+      where
+        tmp_dir = gfo_dir</>tmp
+        cmd = "gf -make -s -optimize-pgf --gfo-dir="++tmp_dir++
+           -- " --output-dir="++grammars_dir++  -- has no effect?!
+              " "++src
+
+execute command =
+  do putStrLn command
+     e <- system command
+     case e of
+       ExitSuccess -> return ()
+       _ -> fail "Command failed"
+     return ()