Implemented REMOTE_USER Authentication

This authentication mode requires an upstream proxy which sets the
REMOTE_USER header. This is rather common in enterprise environments
which use LDAP/Kerberos authentication. This module is largely a copy
of the BrowserID authentication module
Initial conversion of batch scripts to Makefile
Updated to handle commands such as 'make release package'
Copy webapollo config files for package and run targets
Remove bash scripts, add test target to Makefile, remove run target
Use generic MAKE variable in Makefile
Update Install guide introduction
Update install guide
Add a download option for building WebApollo from Makefile
Fix unzip using Makefile
Reverse order or downloads in Makefile
Add some new instructions for building the release
Restructure documentation to smaller pieces
Separate prerequisite documentation page
Allow readthedocs to build without hyperlink
Fix hyperlinks in the documentation
Clarify some documentation
Add additional information on custom builds
Update index.md
Don't redownload files when doing the download-release targets