Revise TokenList2DsnLexer.cmake to take outCppFile and outHeaderFile optinally
and enum mandatorily. Standardize the script's invocation technique within
all the CMakeLists.txt files.
* Add CMake script to generate DSN token header and source file from
token list file.
* Add preliminary component library DSN token list and lexer file to
test script and prepare for new component library file lexer.
* EESchema: right click on ERC check mark displays error in message panel.
* Remove PCBNew header file dependency from common DSN lexer source.
* Minor code clean ups.