Upgraded project to 2018.4.15f1 LTS and Replaced linear brute force reverse curve evaluation with binary search

[llapresi]

• Upgraded project to 2018.4.15f1 LTS
• Replaced linear brute force reverse curve evaluation with binary search
• Replaced non-compiling terrain shader with Standard Shader.

Acceleration curves with a longer length that the default 10 second curve tend to be inaccurate, with acceleration faster than described in the curve.

Increasing the number of iterations of the brute force reverse curve evaluation does solve this problem but I have created a fork and associated pull-request replacing it with a binary search. This changes time complexity to O(log n) rather than O(n), honing in on the correct value in less iterations while allowing for performance tuning by the user.

[SergeyMakeev]

Awesome! Thank you for the contribution!

[llapresi]

Your welcome