Fixed Gateway Crash (for real)

Fixed a bug in BaseGateway that would cause it to still crash servers
during world generation. The import filters must be applied before
searching for doors because GatewayBlockFilter uses Forge-provided block
IDs and not the standard export values. Also fixed a comment in
yCoordHelper that cut off strangely.
Merge remote-tracking branch 'upstream/master'
Merge pull request #132 from SenseiKiwi/master

Fixed Gateway Crash (for real)