Fix Portal Fill Issues

[nicegamer7]

This PR fixes the orientation of the nether_portal blocks placed along the z-axis when filling a portal using flint and steel. This closes #549.

[nicegamer7]

I've just added two commits:

• The first makes sure to use physics on all fill materials except the nether_portal block. The reason for this is that Spigot says in their Javadocs that setting it to false is generally unsafe. The only reason I've set it to false for nether_portal blocks is because after the portal is filled, if the blocks are broken, the console will send an error like this:
  [Server thread/ERROR]: POI data mismatch: never registered at BlockPosition{x=1614, y=64, z=-217}
• The second fixes filling portals with air via an empty bucket. The issue was that the clicked block location was being translated away from the portal, towards the user. But because PlayerBucketFillEvent returns the block that filled the bucket, there was no need to translate the location.

I've tested all these changes on 1.13.2, 1.14.4, and 1.15.2, and they are all working as expected. Lava/Water do not flow, nether_portal blocks are rotated if needed, and portals are filled with air when an empty bucket is filled.

[dumptruckman]

sweet