Always build in the build directory

We can use deploy tasks to build into various directories based
on the version of the repository we have checked out. For standard
use, things should always build in one location locally.
Remove trailing commas in Gruntfile.js to be consistent
Convert other uses of build/version/ to build/, move demo.html
Remove demo.html

One of the reasons demo.html exists in the root of the repository
is because of the versioned build directory. This is no longer
necessary as build/ will be deployed to the tagged location.
Force HTTPS in a few other places
Can now use relative links for demo.html in build directory
Use develop as build_version in develop branch

This is the one portion that we'll need to maintain across versions
so that the compiled files inside the repository can reference the
proper build_version when the build is created.
Merge pull request #112 from washingtonstateuniversity/update/spine-build

[PR] Update Spine build process to be available for multiple deployed versions