message: Fix default build target on visual studio generators
diff: @@ -191,7 +191,9 @@ export abstract class CommonCMakeToolsBase implements api.CMakeToolsAPI {
  * @brief Performs asynchronous extension initialization
  */
  protected async _init(): Promise<CommonCMakeToolsBase> {
  - this._statusBar.targetName = this.defaultBuildTarget;
  + // Setting this will set the string in the statusbar, so we set it here even
  + // though it has the correct default value.
  + this.defaultBuildTarget = null;
  async.exists(this.mainListFile).then(e => this._statusBar.visible = e);
  @@ -374,13 +376,13 @@ export abstract class CommonCMakeToolsBase implements api.CMakeToolsAPI {
  /**
  * @brief The default target to build when no target is specified
  */
  - private _defaultBuildTarget: string = 'all';
  - public get defaultBuildTarget(): string {
  + private _defaultBuildTarget: string|null = null;
  + public get defaultBuildTarget(): string|null {
  return this._defaultBuildTarget;
  }
  - public set defaultBuildTarget(v: string) {
  + public set defaultBuildTarget(v: string|null) {
  this._defaultBuildTarget = v;
  - this._statusBar.targetName = v;
  + this._statusBar.targetName = v || this.allTargetName;
  }
  /**
  