Fix static methods type definitions (thanks @VPagani!)

Improved TypeScript setup

• Added TypeScript linter (dtslint)
• Reorganization of TypeScript declarations

Breaking changes:

• Removed Result.toMaybe() - this method wasn’t commonly used, but pulled in Maybe into compiled bundles, increasing its size.

New features:

• You can now directly import submodules of this package, for example:

  // Previously
  import { Result, Ok, Err } from 'lemons';
  
  // Now possible
  import Result, { Ok, Err } from 'lemons/Result';
  //                               ^^^^^^^^^^^^^
  

  Note that, when importing from the specific modules directly, you'll need to make the main class (in this case Result) a default import instead of a named import.

Misc:

• New build process
• Cleaner/smaller package output