Sections policy

Sections

• add start and end value:
  Section(0f, .6f, 0xFF00FF00.toInt())
• add width and padding to every section.
  every section may have custom width and padding.

  section.width = ..
  section.padding = ..

• support transparent color.
• support NoSection.
• new style, also available in XML sv_sectionStyle:
  • Section.Style.SQUARE
  • Section.Style.ROUND
• add doOnSections extension.

fixes and enhancement

• ImageIndicator accept drawable #171.
• change Interfaces to Function types.
• change OnPrintTickLabel interface to OnPrintTickLabelListener 'typealias'.
• replace SpeedTextFormat with SpeedTextListener 'typealias' #173.
• access to minSpeed & maxSpeed directly.
• fix #169 #172 #174 .