Added XML API Call Support for CRM Modules

Added transparent CRM module access using $CRM->{ModuleName}
Added CRM User Type enum
Implemented getSearchRecords API Call for CRM Modules
Implemented insertRecords CRM API Call for CRM Modules
Implemented getUsers CRM API Call
ZohoCrmModuleIterator consistency fixes for single record and empty result sets
ZohoCrmModuleIterator support for API methods other than getRecords