Remove hard coded attributes in Text Block

[LagTag]

This PR should resolve bbulpett#28 and add the currently hard coded attributes for the FB. I have kept the default value of 4 for max_lines in case any legacy code was relying on that.

label = Zebra::Zpl::Label.new(
:width => 800,
:length => 800,
:print_speed => 6,
:print_density => 5,
:copies => 1
)

label_fed_number = Zebra::Zpl::Text.new(
:data => ("FEDERAL RN#90630 ONT. REG.# 34333"),
:position => [200, 600],
:justification => Zebra::Zpl::Justification::LEFT,
:font_size => Zebra::Zpl::FontSize::SIZE_2,
:width => 200,
:max_lines => 3,
:line_spacing => 3,
:hanging_indent => 20
)
label << label_fed_number
label.dump_contents

^XA^LL800^LH0,0^LS10^PW800^PR6^FWN^CF0,22^CI28^FO200,600^FB800,3,3,L,20^FDFEDERAL RN#90630 ONT. REG.# 34333^FS^PQ1^XZ