Privates

Added a “private” keyword, anything declared private cannot be accessed from outside the current file.

This prevents the user from messing with internal states of libraries they are using

For example, the list library from the standard library.
Now you can’t directly mess with the list pointer

triangles.ptr[5] = ...;

This now results in an error because “ptr” is private!
I also added some small optimizations for lambdas.