[FEATURE] Test initialization of RippleAccountActivityMonitor.
Merge branch 'develop' of github.com:ripple/gatewayd into develop

Conflicts:
	package.json
Merge branch 'develop' of github.com:ripple/gatewayd into develop

Conflicts:
	package.json
[TEST] HTTP Errors for /payments/failed/:id/retry
[TASK] Be explicit with null as callback response.
Merge pull request #175 from ripple/test-http-retry-failed

Looks good to me.