* 'master' of https://github.com/danielgindi/Charts: (23 commits)
  Update ViewPortHandler.swift (ChartsOrg#3143)
  add option to build demo projects unit tests on iOS (ChartsOrg#3121)
  Replaced relevant `ChartUtils` methods with `Double` extensions (ChartsOrg#2994)
  Update 4.0.0 with master (ChartsOrg#3135)
  Removed redundant ivars in BarLineChartViewBase (ChartsOrg#3043)
  fix ChartsOrg#1830. credit from ChartsOrg#2049 (ChartsOrg#2874)
  Makes ChartsDemo compiling again (ChartsOrg#3117)
  Fixed using wrong axis (Issue ChartsOrg#2257)
  Removed methods and properties deprecated in 1.0 (ChartsOrg#2996)
  for ChartsOrg#3061 revert animationUpdate() and animationEnd() not trigger crash if subclass does nothing
  The backing var is not necessary. (ChartsOrg#3000)
  Replaced `ChartUtils.Math` in favour of an extension on `FloatingPoint` (ChartsOrg#2993)
  Minor logic cleanup (ChartsOrg#3041)
  Fix a bug may cause infinite loop. (ChartsOrg#3073)
  for ChartsOrg#2745. chart should be weak.
  fileprivate -> private (ChartsOrg#3042)
  Removed `isKind(of:)`
  Removed @objc from internal properties
  Fixes for PR
  Made use of `==` where appropriate to simplify logic
  ...

# Conflicts:
#	Source/Charts/Data/Implementations/Standard/LineChartDataSet.swift
#	Source/Charts/Renderers/BarChartRenderer.swift