Update podspec

ScrollableGraphView.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
 s.name             = "ScrollableGraphView"
-s.version          = "3.1.0"
+s.version          = "4.0.0"
 s.summary          = "Scrollable graph view for iOS"
 s.description      = "An adaptive scrollable graph view for iOS to visualise simple discrete datasets. Written in Swift."
 s.homepage         = "https://github.com/philackm/Scrollable-GraphView"
@@ -11,6 +11,6 @@ s.platform     = :ios, '8.0'
 s.requires_arc = true
 
 # If more than one source file: https://guides.cocoapods.org/syntax/podspec.html#source_files
-s.source_files = 'Classes/ScrollableGraphView.swift'
+s.source_files = spec.source_files = 'Classes/**/*.swift'
 
 end