Modified the README.md to include a second example where the account SID and
auth token are embedded in the code rather than stored as environmental
variables. This would allow a developer to compile a self-contained executable
that could be run by end users without the need to create or understand
environment variables. Also modified both examples to define sending and
receiving phone number bindings to make it easier for the developer to
read/configure.

Cleared the review notes for commit 2afd62a (modified README for a second
example). Modified the following:
* Used to/from on phone bindings to match with Twilio's RESTful API
* Alphabetized the imports
* Used simpler Data.Text (Text) rather than qualified
* Switched to 2 space indent from 4