fix deadloop when visit ElvisOperatorExpression - #102

Prevent `groovy-all:jar` dependency from breaking resolution

* Add Jenkinsfile support via GDSL and semantic token/highlighting support

Works in VS Code via the https://github.com/cosven/easy-groovy extension

* update readme

* show proper hovers for methods defined in GDSL

* detect methods of supertypes in method call expressions

* Add semantic token support

* manually merge in `semantic-tokens` branch

* Use one output channel instead of creating/deleting several (happens when restarting language server)

* fix vscode extension `range` object access error

* Improved GDSL system by removing hacky workarounds and creating `MethodNode`s on script classes to act as globally available methods

* Hardcode `Map` and `Closure` class checks because Jenkins GDSL provides them unqualified in strings

* Add Maven API to download Jenkins Plugin JARs for typical Jenkins plugins

Inject GDSL property symbols into script classes

Inject methods from `DefaultGroovyMethods` with an `Object` first parameter into `ClassHelper.OBJECT_TYPE`

* Bump LSP4J to 0.20.0 for `CompletionItemLabelDetails` to get a better completion menu for property/method access

* Fix `(DGM)` indicator to be in `CompletionItemLabelDetails.description` to indicate a method as being from `DefaultGroovyMethods`

* Fix property access completion item menus for GDSL global objects

* Modify test cases to check `CompletionItemLabelDetails` and use it for `ClassNode` & `Variable` completions

* Implement go-to-definition for implicit script class `ClassExpression`s and `ImportNode`s where otherwise scripts were required to return an expression (last statement is an expression)

Fix `NullPointerException` when requesting references for a `ClassExpression` of an implicit script class within the same file

Add tests to `GroovyServicesDefinitionTests` for implicit script class definition requests

* Add `dependencies` configuration option to specify maven repository/dependencies to download and use as classpaths

* Send semantic tokens for class symbols/references, including within import statements

* oops should have kept these strings

* Solve the source of the "GDSL globals not being typed" issue

* Add name to copyright notices where I modified code

* Add/modify copyright notices

* Use types of named parameters from GDSL

* Make hovers work on GDSL globals injected as script class fields

* Don't color in undefined nodes, color all Closure variables as functions

* Apply GroovyLanguageServer#102

Prevent `groovy-all:jar` dependency from breaking resolution

* let's not cause the same problem in `HoverProvider`

* Fix `NullPointerException` and change dependency exclusion comment

* Clean up `injectDefaultGroovyMethods` and extend it to all types instead of just `Object`

* Visit all supertypes when getting methods, fields, or properties of a `ClassNode`

Only return public methods/fields/properties

* Restrict hovers and semantic tokens based on member visibility

* HUGE semantic tokens refactor; `def` and `var` are type tokens; hovers on `def` and `var` show the initializing expression's type; `readonly` modifier is working with `final` variables/fields.

* Add self to copyright notices where I modified files