Merge pull request #12 from quamotion/fixes/optional-arguments

source/ChromeDevTools/Protocol/Chrome/Debugger/StackTrace.cs

...tocol/Chrome/Emulation/SetDeviceMetricsOverrideCommand.cs

...rotocol/Chrome/Emulation/SetGeolocationOverrideCommand.cs

...tocol/Chrome/Emulation/SetTouchEmulationEnabledCommand.cs

...evTools/Protocol/Chrome/Emulation/ViewportChangedEvent.cs

source/ChromeDevTools/Protocol/Chrome/FileSystem/Entry.cs

...rome/FileSystem/RequestDirectoryContentCommandResponse.cs

...s/Protocol/Chrome/FileSystem/RequestFileContentCommand.cs

...ol/Chrome/FileSystem/RequestFileContentCommandResponse.cs

...Chrome/FileSystem/RequestFileSystemRootCommandResponse.cs

...tocol/Chrome/FileSystem/RequestMetadataCommandResponse.cs

...Protocol/Chrome/HeapProfiler/AddHeapSnapshotChunkEvent.cs

...col/Chrome/HeapProfiler/GetObjectByHeapObjectIdCommand.cs

...ools/Protocol/Chrome/HeapProfiler/HeapStatsUpdateEvent.cs

...ols/Protocol/Chrome/HeapProfiler/LastSeenObjectIdEvent.cs

...ol/Chrome/HeapProfiler/ReportHeapSnapshotProgressEvent.cs

...vTools/Protocol/Chrome/HeapProfiler/ResetProfilesEvent.cs

...ol/Chrome/HeapProfiler/StartTrackingHeapObjectsCommand.cs

...col/Chrome/HeapProfiler/StopTrackingHeapObjectsCommand.cs

...s/Protocol/Chrome/HeapProfiler/TakeHeapSnapshotCommand.cs