allow path-based custom domains

Before this you had to have a separate domain if you wanted to
use a different developer key and secret. That was lame because
since everything is over SSL it meants having to pass certs
around.
handle empty paths
add path prefix to html links
add ocad logo
logos go in the right spot...
helper for getting badges off the home page faster
js syntax error
new youtube walkthrough
use correct path when generating oauth signature
update docs, clean up unnecessary settings in specs
missed a path_prefix when creating badge links
domain migration support
don't prefix canvas api calls
redirect to new host on access to old host
shuffle badge list
oauth dance needs to know which host to use
handle multiple oauth keys to allow for domain migration
stop pinning gems
update ruby version for travis
Merge remote-tracking branch 'upstream/master' into stable