* introduce IRelativePattern and use in extension API

* 💄

* docs

* introduce RelativePattern

* support RelativePattern also for file watcher

* also make findFiles support RelativePattern

* less type conversion

* add GlobPattern type and remove readonly

* make base a string

* fix setter access to RelativePattern

* fix npe when exclude is undefined

* fix findFiles: pattern seems to be matched against workspace always

* 💄

* clarify glob pattern matching

Have `workspace.applyEdit` correctly account for model version changes and reply with false if a model was loaded and changed in the meantime

Use WorkspaceFolder instead of URIs in IWorkspaceContextService

Fix exclude settings to be resolved against their root folder, not the searchPath, mainly for './' search scenarios

TS 2.3.1 introduced a breaking change by [switching to covariant types for callbacks](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#covariance-in-callback-parameters). This change tries to fix these compiler errors in the workbench codebase