first implementation of reading the ascii_model.
including a test and some documentation
make the test files visible
Create README.md
Merge pull request #67 from wkerzendorf/config/ascii_file_reader

Config/ascii file reader
added atomic symbol reader
added atomic_symbols data file
added reader and file
added tests for atomic2symbol dicts
Merge pull request #69 from wkerzendorf/atomic/atomic_symbols

Atomic/atomic symbols