Update basic auth middleware: Call btoa directly (remove `window` reference)
Update basic auth middleware: Call btoa directly (remove `window` reference)

Signed-off-by: Jesse Stuart <a5c95b3d7cb4d0ae05a15c79c79ab458dc2c8f9e@jessestuart.ca>

jvatic/marbles-js,jvatic/marbles-js