enable apache2 server as front end for swift

1.install apache and wsgi module
2.config apache2 vhost and wsgi files for proxy,
account, container and object server.
3.refactor apache functions from horizon and swift
into lib/apache

Change-Id: I3a5d1e511c5dca1e6d01a1adca8fda0a43d4f632
Implements: blueprint enable-apache-frontend-for-swift
diff --git a/README.md b/README.md
index fbf7b4a..23200e2 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,13 @@
 
     ENABLED_SERVICES="$ENABLED_SERVICES,-rabbit,-zeromq,qpid"
 
+# Apache Frontend
+
+Apache web server is enabled for wsgi services by setting `APACHE_ENABLED_SERVICES` in your localrc. But remember to enable these services at first as above.
+
+Example:
+    APACHE_ENABLED_SERVICES+=keystone,swift
+
 # Swift
 
 Swift is disabled by default.  When enabled, it is configured with