added six-wheeled combined forwarder hsm_940f_combined and four-wheel short forwarder hsm_940f_short

heavy - productive harvester and forwarders, designed for large-scale logging operations.
tried to make interesting, unlike each other and realistic fashion.

in fashion 6 farwarders:
scorpion_king and ponsse_bear have 5 standard trailers and 1 addon.
ponsse_buffalo has 5 standard trailers and 2 add-ons.
john deere has 5 standard trailers and 4 of its add-ons.
the six-wheeled combined forwarder hsm_940f_combined has 5 standard trailers and 6 of its add-ons.
four-wheel short forwarder hsm_940f_short has 6 standard add-ons.

hsm have a large load capacity of 15 tons, are best suited for long distances and ensure compactness and high maneuverability.