restore the FastCGI service and move some files back to src/server

src/server/pgf-fcgi.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE CPP #-}
+import Control.Concurrent(forkIO)
+import Network.FastCGI
+
+import PGFService(cgiMain,newPGFCache,stderrToFile,logFile)
+
+main = do stderrToFile logFile
+          fcgiMain =<< newPGFCache Nothing
+
+
+fcgiMain cache =
+#ifndef mingw32_HOST_OS
+          runFastCGIConcurrent' forkIO 100 (cgiMain cache)
+#else
+          runFastCGI (cgiMain cache)
+#endif