add the ability to plug custom drivers

[roymfibo]

I've created this feature so users could create their own viewers and plug them in when ever they want instead of pull requesting for a viewer.

[pg-infosec]

Vulnerable Package: eslint Affected Range: < 4.18.2 Fixed Version: 4.18.2 Related CVE: WS-2018-0592 Severity: MODERATE

More Information: Please consider upgrading eslint to prevent deploying vulnerable code into production. For more information, visit: https://github.com/eslint/eslint/commit/f6901d0bcf6c918ac4e5c6c7c4bddeb2cb715c09, or visit the FAQ

[pg-infosec]

Vulnerable Package: webpack-dev-server Affected Range: < 3.1.11 Fixed Version: 3.1.11 Related CVE: CVE-2018-14732 Severity: LOW

More Information: Please consider upgrading webpack-dev-server to prevent deploying vulnerable code into production. For more information, visit: https://nvd.nist.gov/vuln/detail/CVE-2018-14732, or visit the FAQ

[eliasor96]

@jonls @wolnewitz

Waiting for your review and approval, please :)

[CLAassistant]

All committers have signed the CLA.