Merge pull request #60 from congbo/master

get rid of the warning when analysing it
NSString -> NSNumber
Merge pull request #61 from cleexiang/master

NSString -> NSNumber
PNLineChart's inflexion Point support two sharp, such as cycle, square
make line more smooth, refactor code
Merge pull request #62 from jackyzonewen/master

PNLineChart's inflexion Point support two sharp, such as cycle, square
Add axis separator
fix bugs that the square style point show immediately
Merge pull request #63 from jackyzonewen/master

Add axis separator
Fix barchart nan bug
Merge pull request #1 from kevinzhow/master

sync