Hotfix V0.5.1 published — RaceLeague Steam update #1405080

Changelog: -Improved and optimized heightmap smoothing tool -Fixed props, prop curves, roads and checkpoints not being set to newly generated terrain -Fixed Cup Car's radiation breaking when hitting kerbs -Fixed checkpoints being invisible in track builder -Fixed database tracks not showing up in track builder -Fixed inability to back out from load track -menu in track builder -Fixed all ground matrials driving like tarmac in track builder test drive -Fixed inability to zoom in and out in track builder after test drive -Fixed some old tracks not loading -Fixed other cars in multiplayer occasionally leaving gravel tire marks on tarmac -Fixed first lap not counting after reset in multiplayer practice and qualifying -Updated Cup car's base setup with a more stable one by Kinichie