Regenerate GAPIC files

[jmuk]

This issue tracks the regeneration process of gapic (auto-generated files). The new auto-generated files have some updates, including:

• class name suffix has changed. Previously -Api, now -Client (like speechClient).
• revised paged iterations style -- previously a stream, now same as what GCN has.
• bug fix on enum values.

Google-cloud-node repository has the the generated files in the following APIs.

• language
• logging
• monitoring
• pubsub
• speech
• vision

[stephenplusplus]

Woo!