Sublime Syntax: Fixes & Improvements

[tajmone]

Tweak the Unicon syntax definition for Sublime Text 3:

• Fix Comments scope:
  • Fix comment.line.double-slash to comment.number-sign.dollar.
• Fix Keywords:
  • Improve readability of reserved and keywords contexts by enabling free-spacing mode in their RegEx definitions.
  • Fix keywords definition which failed to match some keywords.
• Improve Preprocessor:
  • Fix comment.line.double-slash scope to comment.line.dollar.
  • Add meta.preprocessor scope to matched line.
• Improve Operators:
  • Tweak scope from keyword.control to keyword.operator.
  • Extend operators definition to include: % + - ^
• Characters Sets:
  • New context to capture also single-quoted strings.
  • Include escapes sequences context.
• Improve Escape Sequences:
  • Move escapes definition to independent context that can be shared by both double- and single-quoted strings.
  • Tweak RegEx to cover more escape sequence types:
    • Octal escapes.
    • Hex escapes.
    • Control escapes.

[Jafaral]

Thank you very much @tajmone

[Jafaral]

closes #261