Changes
**Note: This release comes with minor behavior changes for tracing closures on PHP 7. Please see [the PR for details](https://github.com/DataDog/dd-trace-php/pull/762).**
### Added
- Service mapping with `DD_SERVICE_MAPPING=pdo:payments-db,mysqli:orders-db` #801, #817
- Auto flushing with `DD_TRACE_AUTO_FLUSH_ENABLED=1` (PHP 7) #819, #826
- Disable automatic root-span creation with `DD_TRACE_GENERATE_ROOT_SPAN=0` #834
### Changed
- Always return unaltered VM dispatch (PHP 7) #762
- Uri to resource name ON by default #798
- Sandbox Guzzle #809, #816
- Sandbox predis integration #813
- Sandbox curl (PHP 7) #814, #817, #831
- Convert pid from long to string for internal spans #825
- Move some Configuration methods to functions written at the C level #829