Adopt tslint in our development

[egamma]

We want to adopt tslint for checking our typescript code.

Most of our style guide should be checked by tslint.

General

• Add initial tslint.json
• Add tslint to our gulp script
• Add a Code task with a problem matcher for tslint
• Document its use in the Contribution Guidelines
• Implement non externalised strings rule
• Add tslint to the pre-commit hygene (wait until we are down to 0 with the warnigs)

Projects

Add tslint checking to other vscode projects

• vscode-omnisharp
• vscode-node-debugger-adapter

Others non-core projects

• vsce
• vscode-vscode

Extensions

• vscode-tslint
• vscode-eslint
• vscode-jslint
• vscode-editorConfig

Rules

• no-unused-expression
• no-unreachable
• no-duplicate-variable
• no-unexternalized-strings
• no-duplicate-key (in object literals)
• no-unused-variable (includes imports) - 500 instances
• curly (braces for if/do/while, in style guide) - 70 instances
• class-name (PacalCased class and interface names), in style guide) - 3
• semicolon (semicolon at end of statements) - 220 instances
• no-unnecessary-semicolons - 60 instances
• no-duplicate-case - 3 instances
• tripple-equals - 10 instances

Candidates

• promise-must-complete - 10 instances (false positives?)
• no-switch-case-fall-through - 25
• forin (for ... statement must be filtered with an if) - 80 instances
• prefer-const (rule is in the TS repository) - ???

Future

• no-var-keyword - 5800
• indent tabs (covered by hygene tasks, in style guide)
• jsdoc-format - 200
• no-trailing-whitespace
• whitespace ...

Rejected

• no-shadowed-variable - 300 instances
• no-string-literal (disallow object access via string literals) - 16
• no-unused-imports (subset of no-unused-variables) - 170 instances
• no-function-expression (use arrow functions, in style guide) - 190 instances
• missing-optional-annotation - 10 instances
• no-use-before-declare
• no-empty-interfaces (we them in our service injection patterns)
• no-multiple-var-decl
• no-missing-visibility-modifiers

[egamma]

Fixed the last tslint warning...