Improve symbol set conversion

[genebeveridge]

Can I proposed some symbol set conversion features that could be arranged into an automated process? Some of these components exist or partially exist.

1. Choose new symbol set without adding a new dialogue window / keep UI limited to conversion window with the option to load external symbol sets for advanced users.
2. Filter out symbol types better (currently there is no distinction between area and line symbols)
3. Check old symbol set for identical names: Count matching words (case insensitive) as portion of total number of words in new symbol name.
4. Check old symbol set for matching symbol numbers. Consider partial / close match with decimals or just 1 number out since this is common between ISOM versions.
5. Check colour of symbols for perfect match or close match.
6. Colour code OOM's confidence based on adding the scores from above to direct the user's attention to where it is needed and not the high confidence matches.
7. Display new and old symbol renders side by side for more reliable error detection by user than just showing icons.