add German signal Bü2 (Rautentafel)
add German signal Bü2 (also with reduced distance) to style
reduce size of circle of arrow of German signal Hp1 (semaphore)
Merge pull request #77 from Nakaner/fix-arrow-DE-hp-semaphore

Reduce Size of Circle of Arrow of German Signal Hp1 (semaphore)
Added german station distant sign (Ne 6 Haltepunkttafel) to signalling layer
Added german station entry sign (Ne 1 Trapeztafel) to signalling layer
Added some german signal icons
Added german main semaphore signals type Hp to signalling layer
Merge pull request #76 from Nakaner/de-bue2

Added german crossing distant signal (Bü 2 Rautentafel) to signalling layer
Added german crossing distant signal (Bü 2 Rautentafel) to signalling layer