WinShell 3.31 major BugFixes/Features to version 3.30

- Update to Scintilla 2.03
- Improved BibTeX Project Window: toggle author/label view, show all entries
- New feature: Autocompletion for LaTeX commands and BibTeX labels
- New feature: Update checker
- New feature: Split/join paragraph
- New option: BibTeX front-end: disable/enable
- New option: Reload open files at startup