Feature: Implement empty BU_

[Murmele]

BU_ field is available, but is empty. According to the documentation there is nothing against an empty BU_ field
http://mcu.so/Microcontroller/Automotive/dbc-file-format-documentation_compress.pdf

VERSION ""


NS_ : 

BS_:

BU_:


BO_ 293 Msg1: 2 Vector__XXX
 SG_ Wert7 : 0|16@1- (1,0) [0|0] "" Vector__XXX

BO_ 292 Msg2: 8 Vector__XXX
 SG_ Wert8 : 56|8@1- (1,0) [0|0] "" Vector__XXX
 SG_ Wert6 : 32|24@1- (1,0) [0|0] "km/h" Vector__XXX
 SG_ Wert5 : 24|8@1- (1,0) [0|0] "" Vector__XXX
 SG_ Wert4 : 0|24@1- (1,0) [0|0] "km/h" Vector__XXX

BO_ 291 Msg3: 8 Vector__XXX
 SG_ Wert3 : 48|16@1- (1,0) [0|0] "" Vector__XXX
 SG_ Wert2 : 24|8@1- (1,0) [0|0] "" Vector__XXX
 SG_ Wert1 : 32|16@1- (1,0) [0|0] "" Vector__XXX
 SG_ Speed : 0|24@1- (1,0) [0|0] "km/h" Vector__XXX

[LinuxDevon]

This is resolved in main now. Will be included in v0.4.0