Vanilla transmissions overhaul v1.0 1.48

Initially the intent of this mod was to remove retarders from ATS vanilla transmissions, as they are not a common thing in the US. Here is the list of improvements to vanilla transmissions:

- Retarder removed from all transmissions.

- For better realism all transmissions are now offered as manual and automated variants (e.g. Eaton Fuller RTLO-20913A manual VS Eaton UltraShift FO-20E313A-MHP automated).

- Transmission names are marked manual (MT), automated (AMT), and automatic (AT) accordingly in their names. Gear names are also improved according to transmission type (e.g. manual gears would read 1L, 1H, 2L, 2H and so on while with AMT chosed you would have 1, 2, 3, 4 and so on).

- Improved gear change sounds - you will hear gear change when using MT, and no sound when using AT or AMT. DT12 will have its common gear change sound (taken from kriechbaum's sound effects mod). For proper manual gear change sound I recommend using kriechbaum's sound pack(s).

- Some transmissions are replaced with other types (specs, ratios, etc) to avoid repetition. This mainly concerns I-Shifts and Allisons.