Refactoring and documentation

lib/squib/api/data.rb

@@ -54,7 +54,7 @@ module Squib
   #   data = csv file: 'data.csv'
   #   => {'h1' => [1,3], 'h2' => [2,4]}
   #
-  # Parsing uses Ruby's CSV, options: {headers: true, converters: :numeric}
+  # Parsing uses Ruby's CSV, with options `{headers: true, converters: :numeric}`
   # http://www.ruby-doc.org/stdlib-2.0/libdoc/csv/rdoc/CSV.html
   #
   # @option opts file [String]  the CSV-formatted file to open. Opens relative to the current directory.

lib/squib/api/units.rb

@@ -1,3 +1,5 @@
+require 'squib/constants'
+
 module Squib
   class Deck
 
@@ -13,7 +15,6 @@ module Squib
       @dpi * n.to_f
     end
 
-    @@INCHES_IN_CM = 0.393700787
     # Given cm, returns the number of pixels according to the deck's DPI.
     #
     # @example
@@ -23,7 +24,7 @@ module Squib
     # @return [Decimal] the number of pixels, according to the deck's DPI
     # @api public
     def cm(n)
-      @dpi * @@INCHES_IN_CM * n.to_f
+      @dpi * Squib::INCHES_IN_CM * n.to_f
     end
 
   end