Fix bar layout bug, pie callback bug

[aoverholtzer]

Fixing two issues:

1. BarChart right/left bar cut in half (Issue BarChart right/left bar cut in half #1446) notes that if you turn on fitBars, the last bar will be cropped out.
2. Tapping on a pie chart slice would not trigger any delegate callbacks (no issue). This is fixed by explicitly requesting callbacks in PieRadarChartViewBase’s tap event.

[liuxuan30]

You mean this happens on Charts v3.0? Not sure if Swift 2.3 branch is the right branch to merge. @danielgindi needs you review on this.

[Huang-Libo]

@aoverholtzer
You help me solve my problem, thanks! I fix my problem on Charts v3.0

@liuxuan30
After I update Charts to Latest commit d1daf3e (Merge pull request #1467 from liuxuan30/baseSDK )，the pie chart's delegate can not be called when I tapped on it. Then I changed Charts' source codes which were metioned in this pull requst, everything works well again.

[danielgindi]

Thank you!

[liuxuan30]

@danielgindi did you notice it's merged into swift 2.3 not master? I am going to porting it to master in #1486