DGS. M-50 customisations and tractive effort modifications

Adds following customisation options to M-50:

-low headlights on both engine and locomotive

-colorable driver and trailing wheel spokes (may be removed in a future update)

-high-mounted class and marker lights, as well as center-mounted markers on locomotive

-optional only cab roof and cab side colorisers (roof and patch)

-toggleable default lettering, plus custom-roadno-custom lettering options

-small and large toggleable cab numbers

-separate driver center colorisers to account for the spokes

-adjusted the toggleable logo

-made the stripes toggleable

-optional classlights

-KsOd's "shields"

-rear low headlights

-DGS' "QJ" style red frame striping and road number may come at a later date

Additionally, adds tender swaps and up powers (the second file), with tender swaps being available for

C-40, C-46, C-55, F-71, P-48 and S-51 tenders

Up powers in ranges of

77, 95, 109 and 125.