Add limit to chart function

Add extra parameters to cancel function

Fix for counting the args

PRICE_FILTER fix: roundTicks now rounds price with tickSize

> roundTicks: Used to round price with tickSize. Example: `roundTicks(0.12345, '0.001') = 0.123`
```php
function roundTicks($price, $tickSize) {
        $precision = strlen(rtrim(substr($tickSize,strpos($tickSize, '.', 1) + 1), '0'));
        return number_format($price, $precision, '.', '');
}
echo roundTicks(0.00016552, '0.00000010');
```

add roundStep functionality, to help with stepSize

```php
    function roundStep($value, $stepSize = 0.1) {
        $precision = strlen(substr(strrchr(rtrim($value,'0'), '.'), 1));
        return round((($value / $stepSize) | 0) * $stepSize, $precision);
    }
```

fix for ultipe redirection modifcation of unknown variable

Merge pull request ccxt#154 from kwshimhyunbo: PUT Method added

PUT Method added

add addtional check for kline chart data

Ad support for downloading CA via proxy

remove path in contrcutor