Jbrowse JBrowse

Merge pull request #127 from mocklerlab/log_fix

Fix to Wiggle track log scale from @mocklerlab / @sallustfire.

BigWig tracks that use the "scale": "log" option do not render properly when the wiggle data includes 0's. This is due to the fact that the origin gets mapped to Infinity. Hence, when the fillRect is invoked on the canvas, nothing is rendered as the height is not finite.

Included is a change that fixes this by mapping 0 to 1, which should be ok for a log scale scale wiggle track.
https://github.com/GMOD/jbrowse/commit/78c7bc8cec1e0542a69acd5488b1...