ZF-16: Add instructions for Zend_Pdf_Color_HTML

Description

Zend_Pdf_Color_HTML allows users to create color objects based on familiar color names and HTML RGB specifications. A primer needs to be added to the zend.pdf.drawing.color section of the manual.

Comments

Assigning to myself since this was my patch.

Fixed priority; not a major issue.

Moving to post 0.1.4 as it is closing down now for release branch

Pushing to 0.2.0; can't finish today.

Changing fix version to 0.6.0.

Done.