Merge pull request #1 from ripple/master

catching up to master
fixed usage syntax for --json flag
Merge branch 'master' of github.com:ripple/gatewayd
[FEATURE] HTTP_SERVER option toggles http server.
[FEATURE] Accept api key in username or password, deprecate admin@domain.com
[TASK] Add empty logs for development, staging, and production
[TASK] Change .gitignore to ignore logs
Merge pull request #254 from ripple/logfile

[TASK] Add empty log files for development, staging, and production
Merge pull request #251 from ripple/no-username-auth

No username auth
Merge pull request #250 from ripple/http-server-toggle

[FEATURE] HTTP_SERVER option toggles http server.
removed outdated/incomplete docs and added link to dev portal
Merge pull request #256 from ripple/release-3.24.2-rc1

Release 3.24.2 rc1
Merge branch 'master' of github.com:ripple/gatewayd
[TASK] Bump patch version and release notes.
Merge pull request #258 from ripple/release-3.25.1-rc1

Release 3.25.1 rc1
Merge branch 'master' of github.com:ripple/gatewayd
Merge pull request #259 from mDuo13/new_readme

New simpler readme, removed outdated docs [2]
[DOC] Add installation guide for Mac
[FEATURE] Reorganize ProcessManager, create ProcessSet.

[TASK] Rename GatewayProcessManager to ProcessManager.

[TASK] Rename GatewaydProcessSet to ProcessSet.
Merge pull request #266 from ripple/develop

[DOC] Move api, install documentation to dev.ripple.com