py2js parentheses bug

[Hemml]

in if-statements some parentheses can be lost.
This code:

if a==b or (c==d and d==e):

alert("QQ")

translates to:

if ((a == b)

(c == d) && (d == e)) {

alert("QQ");

}

but must be translated to:

if ((a == b)

((c == d) && (d == e))) {

alert("QQ");

}

[apoirier]

(In [5bced6e5760a46904dc6a4595455069c3e4e9d10]) Fixes #48.
Boolean expressions parenthesis handling backported from the lastest version of pyjs.