Allow zero and negative values in logarithmic axes
where:
log(0) === 0
log (x) === log(x) * 1

I'm not sure how such a scale should be implemented in practice. What tick would be next to 0?
For example, we could have ticks for 100, 10, 1, 0, 1, 10, 100. But this means two discontinuous scales, because the true logarithmic scale doesn't reach 0 at all. It could just as well be 100, 1, 0.01, 0, 0.01, 1, 100. So should we add options for where to cut off close to 0?

Ecehan Ece commented
We are using highcharts as a company and dealing with negative values along with positives. Could you please consider to support zeror and negative values in logarithmic axes?

John commented
Example of people needing this:
http://stackoverflow.com/questions/19447408/highchartsdisplayingzerovaluesinlogarithmicscale
http://stackoverflow.com/questions/15498740/logarithmicchartwith0values
http://forum.highcharts.com/highmapsusagef14/negativeand0valueswithlogarithmicaxist30868/