added shared and __src_version__ to library doc

doc/library/index.txt

@@ -32,6 +32,10 @@ There are also some top-level imports that you might find more convenient:
     
     Alias for :func:`function.function`
 
+.. function:: shared(...)
+    
+    Alias for :func:`shared.shared`
+
 .. class:: Param
 
     Alias for :class:`function.Param`
@@ -40,3 +44,12 @@ There are also some top-level imports that you might find more convenient:
 
     Works like :func:`tensor.dot` for both sparse and dense matrix products
 
+
+.. function:: __src_version__()
+
+    Returns the mercurial (hg) identifier of the current tip.  
+    
+    If there are uncommitted modifications, this function raises an Exception.
+    If the theano package is not under mercurial control, then again this function
+    raises an Exception.
+