Add portal events and Maven project

- Make Maven project
- Add custom events related to portals
Update PortalCreateEvent.java

Fix indent
Add incomplete event listeners
Merge branch 'master' of https://github.com/PortalAPIDevGroup/PortalAPI

Conflicts:

src/main/java/org/spongepowered/community/portalapi/events/PortalActivat
eEvent.java
Merge pull request #1 from PortalAPIDevGroup/master

Maven project and events