Visual tweaks
Nit
Create README.md
Change URL for 0.2.0.
Merge pull request #2 from Natim/0.2.0_dev_compliant

Change URL for 0.2.0.
Implements the new workflow.
Fix register arguments.
Remove closure that is hidding the callback variable.
Fix the certificateSign method.
Fix MSISDN not mandatory.
Merge pull request #3 from Natim/0.4.1_new_worflow

New 0.4.1 API workflow
add server text field, add hints for USA values
Add the MCC parameter to the sms/mt/verify and handle the 204 status code.
Make the server configurable.