Strips all tokens from string.

@example 'install <dir> [filename]' >> 'install dir filename'

@param val the val containing tokens to be stripped.
@param negate the negation char used.
@param variadic the variadic char used.
function stripTokens(val, negate, variadic) {
    variadic = escape(variadic || constants_1.VARIADIC_CHAR);
    negate = escape(negate || constants_1.NEGATE_CHAR);
    var argExp = new RegExp(['<', '>', '\\[', '\\]'].join('|'), 'g');
    var noExp = new RegExp('^' + negate);
    var variExp = new RegExp(variadic + '$');
    return expandArgs(val)
        .map(function (v) {
        v = v
            .replace(constants_1.FLAG_EXP, '')
            .replace(noExp, '')
            .replace(argExp, '')
            .replace(variExp, '');
        return v;
    }).join(' ');
}