v38.0.0

New and notable:

• fixes for deleting digitalocean droplets #387
• migrate to typings #382
• migrate to ssh2 0.5 #386

Other changes:

• fix the slow integration tests #384
• delegate arraybuffers functions to Buffer, where possible, and remove some unused functions #391 and #390
• remove unused accumulator class #389

Compatibility table (getters are rows, givers columns):

*	chrome-stable	chrome-beta	chrome-canary	firefox-stable	firefox-beta	firefox-canary
chrome-stable	✅	✅	✅	✅	✅	✅
chrome-beta	✅	✅	✅	✅	✅	✅
chrome-canary	✅	✅	✅	✅	✅	✅
firefox-stable	✅	✅	✅	✅	✅	✅
firefox-beta	✅	✅	✅	✅	✅	✅
firefox-canary	✅	✅	✅	✅	✅	✅