This is a good video guide from Joker which explains what you need to do.
Basically you need to...
1. Go to your Steam folder (/ Program Files (x86) / Steam)
2. Open the userdata folder
3. Look for the folder number 287700
5. Click the Local folder and open TPP_GRAPHICS_CONFIG in notepad.
6. Now change "framerate_control" : "Auto" to "framerate_control" : "Variable"
7. Save and then launch the game.
The framerate should no longer be capped.