[ADD] sms notifications; [ADD] on call timeperiod;
[CHANGE] abstract gateway url on sms notifications script;
[CHANGE] added missing attribute
[CHANGE] removed unnecessary protocols on Berksfile; [CHANGE] abstracted notification attributes a bit more; [ADD] attribute to disable certain notification methods by environment;
[CHANGE] added php5-curl requirement to readme; [CHANGE] fix default for sms notification disabled;
[CHANGE] fixed some typos on checknames;
Merge pull request #74 from Bigpoint/sms-notifications

[ADD] sms notifications; [ADD] on call timeperiod;