iOS / PNChart

Feature/ib support

Update method name

It could be an issue if we have a property named as defaultValues later.

Make delegate methods optional

They should be optional methods so we can get rid of warning when only using one kind of these chart.

Fixing Issue #104

* Multiple lines of text in UILabel

X Labels Autoshrink for PNBarChart.

Fixing Issue #75

Feature Scatter Graph

* this is compatible with new release.
* because of your huge change, I had to change the position of my codes
from viewController to tableViewController.
* minor changing and improvement.

PNScatterChart in UIView

** scatter chart programmatically
** adding header to header files

* tableView in Main.storyboard

Conflicts:
	PNChart.podspec