Initial implementation of double-with and double-heigh text in html.

[mike42]

This pull request implements double-height and double-width text at a line-level. This is triggered by SelectPrintModeCmd or SelectCharacterSizeCmd. 1x1, 1x2, 2x1 and 2x2 are all supported, with higher multiples capped for some compatibility (eg attempting 4x width will cause 2x width to be used).

Some unrelated bug fixes are also included-

• 2D data code parsing caused a 'class not found' due to a typo
• Emphasis was not applied to SelectPrintModeCmd.

Switching the values mid-line does work, but the character alignment (width and height) is quite buggy.

• Multiple heights should go to baseline
• Multiple widths should not overlap

This will require a lot of re-work to display perfectly, and is not as important as some other missing features, so I'm submitting this as-is.

Example from #8-

Larger example showing heights for #12, outstanding rendering issues-

Reference-

• 8

• 12