Add new Version property to handle joined version numbers (#2062)

* Add new version property to handle joined version numbers

* Add unit test for new joined property

* Add documentation on version.up_to() and version.joined

var/spack/repos/builtin/packages/cryptopp/package.py

@@ -36,12 +36,15 @@ class Cryptopp(Package):
     """
 
     homepage = "http://www.cryptopp.com"
-    base_url = "http://www.cryptopp.com"
 
     version('5.6.3', '3c5b70e2ec98b7a24988734446242d07')
     version('5.6.2', '7ed022585698df48e65ce9218f6c6a67')
     version('5.6.1', '96cbeba0907562b077e26bcffb483828')
 
+    def url_for_version(self, version):
+        url = "{0}/{1}{2}.zip"
+        return url.format(self.homepage, self.name, version.joined)
+
     def install(self, spec, prefix):
         make()
 
@@ -51,7 +54,3 @@ def install(self, spec, prefix):
 
         mkdirp(prefix.lib)
         install('libcryptopp.a', prefix.lib)
-
-    def url_for_version(self, version):
-        version_string = str(version).replace('.', '')
-        return '%s/cryptopp%s.zip' % (Cryptopp.base_url, version_string)