add fonts methods

Fixes #334

docs/dsl/print_system_fonts.rst

@@ -0,0 +1,20 @@
+print_system_fonts
+==================
+
+Returns an array of font names that Squib knows about. These are what Squib considers "system" fonts. For debugging purposes.
+
+This is a module function, so it can be called anywhere with ``Squib.print_system_fonts``
+
+
+Options
+-------
+
+None.
+
+
+Examples
+--------
+
+.. literalinclude:: ../../samples/system_font_debug/_list_fonts.rb
+  :language: ruby
+  :linenos:

docs/dsl/system_fonts.rst

@@ -0,0 +1,19 @@
+system_fonts
+============
+
+Returns an array of font names that Squib knows about. These are what Squib considers "system" fonts. For debugging purposes.
+
+This is a module function, so it can be called anywhere with ``Squib.system_fonts``
+
+Options
+-------
+
+None.
+
+
+Examples
+--------
+
+.. literalinclude:: ../../samples/system_font_debug/_list_fonts.rb
+  :language: ruby
+  :linenos: