**New Features**
* Added an "Internals" System. You can now add any instance derived from BaseInternal to the internals list of a unit operation. These internals can represent tubes in a heat exchanger, trays or packing in a column, or special realisations of pumps and compressors.
**Breaking Change**: It is not possible to define internals by a string anymore.
python
U3=pfd.unit(Vessel("Fermenter","Fermenter", position=(200,190), capLength=20, showCapLines=False, size=(80,140),internals=[Stirrer(type=StirrerType.Anchor), Jacket()] ))
* Changed how vertical/horizontal vessels work: Now every vessel is vertical by default, but can be rotated either with the rotate(angle) method or by passing the angle as parameter into the constructor.
python
BA11=Vessel("DS10-BA11","Horizontal Vessel", angle=90, position=(560,400), size=(40,100), capLength=20,internals=[CatalystBed()] )
* Compressor unit operation
**Bugfixes**
* Multiple calls to .rotate(angle) do not rotate the ports anymore while keeping the unit itself at the same angle.
* Rotating a unit now influences the area that is blocked for pathfinding.