Fixes Rxjs 6 compatibility #5

[berga]

I've changed a bit the package requirements:

• electron updated to ^2.0.2
• rxjs updated to ^6.2.0

tests have been fixed and run successfully

I've updated the package version to reflect rxjs semver

[colinskow]

Thank you very much for this! I hadn't been checking my notifications and just noticed. I will review and merge shortly.

[alexstrat]

👋 @colinskow do you have a chance to review and publish this? :)

[beorn]

Any update? This fork also contains some nice improvements: https://github.com/getstation/rx-ipc-electron