Add font support for alchemical symbols

[josieg]

In the Introductory Chemistry book, there are a number of symbols that are not displayed properly in the PDF. I've copied the PDF error report below. To fix, would need to add font support for alchemical symbols.

Array
(
[time] => Mon May 8 18:07:45 2017
[user] => jgray
[site_url] => https://opentextbc.ca/introductorychemistry
[blog_id] => 17
[theme] => Open Textbooks
[url] => https://opentextbc.ca/introductorychemistry/format/xhtml?timestamp=1494266789&hashkey=48a9256d3373eb61dbc357de77dad646
)
Mon May 8 11:06:30 2017: ---- begin
Mon May 8 11:06:44 2017: page 211: warning: no font for Arrows character U+21D4, fallback to '?'
Mon May 8 11:06:44 2017: page 242: warning: no font for Emoticons character U+1F62F, fallback to '?'
Mon May 8 11:06:45 2017: page 346: warning: no font for Mathematical Operators character U+221D, fallback to '?'
Mon May 8 11:06:45 2017: page 346: warning: no font for Mathematical Operators character U+22C5, fallback to '?'
Mon May 8 11:06:47 2017: page 596: warning: no font for Arrows character U+21C4, fallback to '?'
Mon May 8 11:06:47 2017: page 662: warning: no font for Arrows character U+21C4, fallback to '?'
Mon May 8 11:06:48 2017: page 729: warning: no font for Mathematical Operators character U+223C, fallback to '~'
Mon May 8 11:06:49 2017: page 875: warning: no font for Arrows character U+21CC, fallback to '?'
Mon May 8 11:06:49 2017: page 900: warning: no font for Superscripts and Subscripts character U+2070, fallback to '?'
Mon May 8 11:06:49 2017: page 900: warning: no font for Superscripts and Subscripts character U+2070, fallback to '?'
Mon May 8 11:06:49 2017: page 910: warning: no font for Superscripts and Subscripts character U+2070, fallback to '?'
Mon May 8 11:07:00 2017: error: PDF/X-1a:2003 does not support transparent images
Mon May 8 11:07:45 2017: finished: success
Mon May 8 11:07:45 2017: ---- end