Merge pull request #50 from moflo/master

Updated circle chart API
Fix podspec
Lots of new API for Bar Chart
Fix Bar chart x label position
Convert to modern Objective-C syntax
Remove unused values in data list

The size of xLabels is 5, but the size of array on getData is 7.
I changed 7 to 5 one on getData.
It is more clear.
Merge pull request #52 from rochefort/fix-readme

Remove unused values in data list
Merge pull request #51 from rochefort/modern-syntax

Convert to modern Objective-C syntax
PNPieChart

Simple Pie chart.
fix typo
Merge pull request #53 from ZhangHang/master

Simple Pie chart for PNChart
Fix pie chart style
Fix readme
Update README.md
Fix color
Fix Color
Remove color
[Mod] : Add Coodinate Axis to PNLineChart
Merge pull request #54 from jackyzonewen/master

[Mod] : Add Coodinate Axis to PNLineChart
Made counting label publicly accessible. Adding ability to grow circle.