new tests file, and fixes for '-' unordered list items and '====' heading indicators, and fixed styles for twilight and default
1. added tests.md to list out the different markdown syntaxes tested, with bugs
2. in twilight/userDefineLang.xml and default/userDefineLang.xml added in '-' as an operator so that it can be used in a similar fashion to '+' as an unordered list item, also changed the '---' keywords to be 'prefix keywords' and added in '===' so that any heading line longer than 3 -/= characters will be shown as a heading line
3. in twilight/userDefineLang.xml and default/userDefineLang.xml sorted the colours/styles so that they match the appropriate keywords/delimiters e.g. for all the link colouring, the italic and bold+italic, operators