Add INSTALL file for python bindings. Add note about libtool to INSTALL of c runtime

src/runtime/c/INSTALL

@@ -1,3 +1,5 @@
+You will need the package: libtool
+
 The compilation steps are:
 
 $ autoreconf -i
@@ -26,4 +28,3 @@ $ autoreconf -i
 $ ./configure
 $ make
 $ make install
-

src/runtime/python/INSTALL

@@ -0,0 +1,5 @@
+You will need the python-devel package or similar.
+You must have installed the PGF C runtime (see ../c/INSTALL)
+
+$ python setup.py build
+$ sudo python setup.py install