Binary operators ignore surrounding brackets

[baurse]

Right now, all binary operators ignore possible surrounding brackets, even if they are significant for the code logic.
For example the following
a = k * (qx + qw)
is incorrectly treated as equivalent to
a = k * qx + qw
and actually converted into the latter by the parser.

This is, obviously, very bad and very wrong

[baurse]

Mostly fixed this in commits 8f741b5 and 2e419dc
it now adds unnecessary parenthesis sometimes, but seemingly only when it doesn't change the code logic. See e.g. the currently skipped test_arithmetic_operations_with_parenthesis_1