Updated the sc, ss, sg, and sdb functions so they make use of the rails binstub (if it exists).
Updated the "ber" alias to be a function.

* Updated associated aliases and functions that rely on "ber" so that auto-execution
  of rake will be done via binstub or bundle exec.
Updated the "bes" alias to be a function.

* Updated associated aliases and functions that rely on "bes" so that auto-execution
  of rspec will be done via binstub or bundle exec.
Updated the "bec" alias to be a function.

* Updated associated aliases and functions that rely on "bec" so that auto-execution
  of rake will be done via binstub or bundle exec.