Inline functions

[eliassjogreen]

Proposal to add inline functions using the inline keyword:

export inline fn test_inline(a: i32): u32 {
  return a as u32
}

This would most likely be implement by adding another field to the Compiler struct which contains the instructions for each registered inline function. This is useful for things like std/math, and other high performance, or small tasks where a function call is not desired.