Relax whitespace rules around operators

[farism]

The compiler could allow all of the following syntax

let a=2
let b = a|>Number.toString
let neq = a!=1
let eq = foo==2
let lte = a<=3
let lt = a<3
let gte = a>=1
let gt = a>1
let plus = a+1
let multiply = a*2
let divide = a/2
let mod = a%2==0
let exp = 2**3
let and = a==2&&a==2
let ortest = a==1||a==2
let true = ! false

Special consideration needs to be taken for

- because - is ambiguous with negative values
or because it the characters "or" can be used in variable names

In addition to relaxing the syntax, if there is no whitespace surrounding an operator, then whitespace should be inserted by the formatter. Not sure if that should be a separate issue.

[farism]

Related #397