Split test into two sub tests, removed unused imports

- Split test into test Element and test for Entity
- Removed some unused imports
Minor doc cleanup
Add inline directives to simple functions
Refactor functions

- Moved state fro getter functions to `parse_char` TODO move all
  other state to `parse_char` function
- Renamed `get_attl_quote` to `get_spec_quote`
Add test for parsing % in !ENTITY declarations
Make tests pass for !ENTITY list
Added more tests
Make it so tests pass for parsing Entity values