A bit of overall refactoring

[nene]

The code of atom-lebab has grown a bit hairy, so I decided to do some clean-up:

• Extracted the main logic into a class, so the editor instance can be stored in a field and easily accessed by all methods.
• Extracted bunch of helper methods to divide the larger ones into more manageable pieces.
• Rewrote uses of forEach() with map() and filter().
• Eliminated most of the variables - using methods instead.
• Simplified conditional logic:
  • replaced a && b || c with a ? b : c
  • replaced newline insertion with .join("\n")
• Remove export of convert()
• Remove try-catch that hides away errors

[ga2mer]

If you have not finished, you forgot transforms in lebab.transform

[nene]

Yeah... the last commit went a bit wrong... did --force push to correct it.