Update pl_PL.lang

Translated lacking lines, moved lines to mach en_US.lang file, changed translation for some items and blocks and changed big letter for second and later words as there is no such thing in polish if it's not invented name which they aren't.
Fix ElectricBlocks not accepting from IC2. Stuff seems to come from UNKNOWN a lot...
Remove IC2 reception support from UniCables. Fixes #1123 and #1280.
Make universal cables pull from IC2 Sources when in PULL mode.

This concludes work on making our IC2 support not suck.
Work on localisations and Item rendering.