Add EditorConfig Settings and Travis CI Tests

[tajmone]

WIP — These features are under development in the editorconfig branch.

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Improve repository template by adding:

• EditorConfig settings to enforce consistent code styles across editors and IDEs (detected natively by many editors, or via plugins).
  • Define code rules for common file types expected in PureBasic projects, following best-practices recommendations:
    • Repository Configurations
    • PureBasic Files
    • Batch Scripts
    • Shell Scripts
    • Markdown GFM
    • Plain-Text Files
• Travis CI job to validate EditorConfig compliance of commits and PRs via EClint (Node.js).
• Document new features in README file.