Refactor: remove unused using statements
Modify test to use the new API
Allow using a string as comment delimiter instead of a char
Merge branch 'feature/allow_multicharacter_comments' into development

* feature/allow_multicharacter_comments:
  Allow using a string as comment delimiter instead of a char
  Modify test to use the new API
Modified parsing behaviour for the common defaults:

 - Comments are now line-based, so comment lines must start
   with the comment char (;)
 - Comments at the end of a section are now saved (there were previously lost)
   in the TrailingComments property of a SectionData.
 - SectionData.AllComments returns both the Comments and Trailing comments
Changed SectionData propery names:

 - SectionData.Comments became SectionData.LeadingComments
 - SectionData.TrailingComments remains unchanged
 - SectionData.AllComments became SectionData.Comments
Fix test ini format