Include the Unicode Name in the missing character output

[davelab6]

https://bitbucket.org/sortsmill/libunicodenames has python support.

• [x] check if it is installed
• [x] if installed, use it to include character names whenever a single character is used
• [x] if not installed, print a warning about this as the program ends

Example, was

Orthography:
        Common Name: GWF latin
        Native Name: 
        Support Level: partial
        Percent coverage: 97
        Missing values: U+0020 ( ), U+00a0 ( ), U+00a4 (¤), U+00ad (­), U+2074 (⁴), U+2215 (∕)

should be with it installed,

Orthography:
        Common Name: GWF latin
        Native Name: 
        Support Level: partial
        Percent coverage: 97
        Missing values:
                U+0020   space
                U+00a0   nonbreakingspace
                U+00a4 ¤ currency
                U+00ad   something
                U+2074 ⁴ ordinalfour
                U+2215 ∕ divide, 

and without it installed

Orthography:
        Common Name: GWF latin
        Native Name: 
        Support Level: partial
        Percent coverage: 97
        Missing values:
                U+0020   
                U+00a0   
                U+00a4 ¤ 
                U+00ad   
                U+2074 ⁴ 
                U+2215 ∕