Removing namespace Import

• moved classes from Import to main namespace
• change is backwards compatible (added Plan and DataSource placeholders back to Import)
• all moved classes have deprecated subclasses in their original places
• will cause problems if you use /ChartMogul and use /ChartMogul/Import, then just remove the second use.

Fixes

• DataSource has system property now
• Customer is consolidated (has all methods), Import\Customer and Customers are deprecated and will be removed in future versions.
• minor/formatting fixes

Simplified namespaces

• moved classes DataSource, Customer, Plan to main namespace
• added Ping->ping
• added Subscription->setCancellationDates
• fixed Customer->get

Minor fixes

Fix of compatibility with PHP 5.x (namespace clashes)