isActive method could give NullPointerException

A pump with an empty "block list" would cause NullPointerException if
isActive was called.
Update PipeTransportPower.java

fixes #1120
fixes #1120 again

<CovertJaguar> though personally it would be better to make the hook return the value to adjust it by
Merge pull request #1118 from SandGrainOne/master

isActive method can give NullPointerException
Merge pull request #1112 from ItsMeElConquistador/master

Fix pipe rendering (issue #1111)
Clean code while debug Diamond Pipe

Conclusion, any issues that people have with Diamond Pipes and AE
machines, are likely AE's fault. Cannot duplicate.

Closes #1005
Add Floodgate Recipe

Oops

Closes #1122
Fix pipe selection box sync

Closes #1104

Also, pipes were running server code on the client. This is bad, fixed.

And killed the dead PipeRenderStatePacket.
Minor Power API tweak

This should allow tickless systems to function properly.

And for the record, this whole "tickless" requirement is more CPU costly
than a simple update tick would be. *shakes fist at Aiden*
Double Iron Engine cooldown speed