look for symbols in content dictionaries; add setname1 content dictionary
look for symbols in content dictionaries; add setname1 content dictionary

fixes #26

csymbol tags will look for their content in CToP.contentDictionaries[cd] if the `cd` attribute is given.
This commit adds the setname1 content dictionary to give blackboard bold C,N,P,Q,R and Z.

mathjax/ctop