Added Python Twisted library

var/spack/packages/py-twisted/package.py

@@ -0,0 +1,16 @@
+from spack import *
+
+class PyTwisted(Package):
+    """An asynchronous networking framework written in Python"""
+    homepage = "https://twistedmatrix.com/"
+    url      = "https://pypi.python.org/packages/source/T/Twisted/Twisted-15.3.0.tar.bz2"
+
+    version('15.4.0', '5337ffb6aeeff3790981a2cd56db9655')
+    version('15.3.0', 'b58e83da2f00b3352afad74d0c5c4599')
+
+    depends_on('py-setuptools')
+
+    extends('python')
+
+    def install(self, spec, prefix):
+        python('setup.py', 'install', '--prefix=%s' % prefix)