SCIL-25: Update of control flow, native bool support, documentation

[troelsfr]

This PR introduces a bunch of updates. Those includes native bool support (EVM comapitble as opposed to used defined bools which are not EVM compatible) type deduction, introduction of wildcards in match statement and improved symbols.

scilla_version 0

library HelloWorld

contract HelloWorld()

transition setHello (msg: Uint64)
  address = 0x0012;
  test = Uint64 42;
  is_owner = builtin eq msg test;
  test2 = False;
  is_false = builtin eq test2 is_owner;
  match is_false with
  | True =>
    msg = "The values were different";
    print msg
  | _ =>
    msg = "The values were equal";
    print msg
  end
end

Further, this PR fixes many warnings, removes unused code and adds additional documentation.