Sensibility does not work for Bar Charts

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Make a Bar Chart
2. Set the Sensibility to any value
3. flotr only registers a hit when the mouse is directly on top of the bars

What is the expected output? What do you see instead?
A hit registered when the mouse is on top of the bars or when the mouse is 
close to the bars per the sensibility. Instead it only works when the mouse is 
directly on top of the bars.

What version of the product are you using? On what operating system?
most recent trunk (r174)

Please provide any additional information below.
A patch that I created is attached. It works for me, and as far as I can tell 
should be correct... I don't know if this is really a 'bug' but it was 
unexpected behavior for me at least and it isn't documented that sensibility 
does not apply for bar charts.

This is only a problem when the bars are very small. (I encountered it when 
making a chart displaying a whole year with individual bars for each day)

Original issue reported on code.google.com by alla...@gmail.com on 21 Dec 2010 at 1:04

[GoogleCodeExporter]

Nevermind, the patch I had previously included introduced more bugs than it 
fixed. I've deleted it now.

Original comment by alla...@gmail.com on 9 Jan 2011 at 10:45