Add back the ability to specify a http client as part of the ctor.
Add back the ability to specify a http client as part of the ctor.

beachboysapp/urgentMe,MartinAmps/twilio-php,achoe/twilio-php,sayan801/twilio-php,pablophg/twilio-php,Git-Host/twilio-php,beachboysapp/urgentMe,FTrubitz/twilio-php,twilio/twilio-php,javierwilson/twilio-php