Lower engine heat 10 times

I don't think a temperature of 10000°C or 0°C doesn't make sense. This way it will at least always be under the melting point of iron and above the freezing point of water.
Merge pull request #833 from viliml/patch-1

Lower engine heat 10 times
Backport for TFC

- forge 7.7.1.629 (same as TFC)
- fluid fix because TFC replaces water and lava (LiquidRendere.java and
GuiCombustionEngine.java)
Merge remote-tracking branch 'upstream/master'