Add Frege language

What is Frege?
-------------
Frege is a non-strict, pure functional programming language in the spirit of Haskell for the JVM.
It enjoys a strong static type system with type inference.
Higher rank types are supported, though type annotations are required for that.

Frege programs are compiled to Java and run in a JVM.
Existing Java Classes and Methods can be used seamlessly from Frege.

The Frege programming language is named after and in honor of Gottlob Frege.

Project State:
-------------
The compiler, an Eclipse plugin and a provisional version of the documentation can be downloaded
from here https://github.com/Frege/frege/releases.

The REPL can be downloaded from here
https://github.com/Frege/frege-repl/releases.

An online REPL is running here
http://try.frege-lang.org/.

Examples:
--------
1) Command Line Clock: https://github.com/Frege/frege/blob/master/examples/CommandLineClock.fr
2) Brainfuck: https://github.com/Frege/frege/blob/master/examples/Brainfuck.fr
3) Concurrency: https://github.com/Frege/frege/blob/master/examples/Concurrent.fr
4) Sudoku: https://github.com/Frege/frege/blob/master/examples/Sudoku.fr
5) Java Swing examples: https://github.com/Frege/frege/blob/master/examples/SwingExamples.fr

samples/Frege/CommandLineClock.fr

@@ -0,0 +1,44 @@
+{-- 
+    This program displays the
+    current time on stdandard output
+    every other second.
+    -}
+    
+module examples.CommandLineClock where
+
+data Date = native java.util.Date where
+    native new :: () -> IO (MutableIO Date)     -- new Date()
+    native toString :: Mutable s Date -> ST s String    -- d.toString()
+
+--- 'IO' action to give us the current time as 'String'
+current :: IO String
+current = do
+    d <- Date.new ()
+    d.toString
+
+{- 
+    "java.lang.Thread.sleep" takes a "long" and
+    returns nothing, but may throw an InterruptedException.
+    This is without doubt an IO action.
+    
+    public static void sleep(long millis)
+                  throws InterruptedException
+    
+    Encoded in Frege:
+    - argument type  long   Long
+    - result         void   ()
+    - does IO               IO ()
+    - throws ...            throws ....
+     
+-}
+-- .... defined in frege.java.Lang
+-- native sleep java.lang.Thread.sleep :: Long -> IO () throws InterruptedException
+
+      
+main args =  
+    forever do
+        current >>= print
+        print "\r"
+        stdout.flush
+        Thread.sleep 999
+