Adding Excel xlsx support and prefixed images

* New sample!
* New API function!
* Ignoring _img in samples

lib/squib/api/data.rb

@@ -1,4 +1,4 @@
-require 'spreadsheet'
+require 'roo'
 
 module Squib
   class Deck
@@ -7,8 +7,23 @@ module Squib
       raise 'Not implemented!'
     end
 
-    def xls(file: 'data.xls', sheet: 0)
-      
-    end
+    def xlsx(file: 'deck.xlsx', sheet: 0)
+      s = Roo::Excelx.new(file)
+      s.default_sheet = s.sheets.first
+      data = {}
+      s.first_column.upto(s.last_column) do |col|
+        header = s.cell(s.first_row,col).to_s
+        data[header] = []
+        (s.first_row+1).upto(s.last_row) do |row|
+          cell = s.cell(row,col)
+          # Roo hack for avoiding unnecessary .0's on whole integers
+          cell = s.excelx_value(row,col) if s.excelx_type(row,col) == [:numeric_or_formula, "General"]
+          data[header] << cell
+        end#row
+      end#col
+      data
+    end#xlsx
+
   end
-end
+end
+

lib/squib/api/save.rb

@@ -1,15 +1,15 @@
 module Squib
   class Deck
   
-    def save(range: :all, format: :png)
+    def save(range: :all, format: :png, prefix: "card_")
       format = [format].flatten
-      save_png(range: range) if format.include? :png
+      save_png(range: range, prefix: prefix) if format.include? :png
       save_pdf if format.include? :pdf
     end
     
-    def save_png(range: :all)
+    def save_png(range: :all, dir: "_img", prefix: 'card_')
       range = rangeify(range)
-      range.each { |i| @cards[i].save_png(i) }
+      range.each { |i| @cards[i].save_png(i, dir, prefix) }
     end
 
   end