`drawPoints` does not handle points with floating point values

[opatiny]

I had to draw points for a test case and drawPoints was ignoring some of my points, which seemed like a very unexpected behaviour. I realised that some of the points were not whole values.

We should handle floating point values, either:

• throw an error and force user to pass integers
• round the points in the function before drawing them

@targos, wdyt?

[targos]

Let's Math.round, and do the same in other draw functions. I expect the result to be closer to what we would have with a continuous plane.

[opatiny]

This is actually an issue in many functions, I've just had it in copyToas well.

[opatiny]

This is actually an issue in many functions, I've just had it in copyToas well.

@targos, in the case of copyTo we said that we would like to throw instead of rounding right?

[targos]

Yes