message: use fs for version check
diff: import * as cp from 'child_process';
  import * as fs from 'fs';
  +import * as path from 'path';
  import ChildProcess = cp.ChildProcess;
  import * as SemVer from 'semver';
  @@ -185,7 +186,7 @@ export class LanguageClient extends BaseLanguageClient {
  }
  private checkVersion() {
  - let packageJson: PackageJson = require('../package.json');
  + let packageJson: PackageJson = JSON.parse(fs.readFileSync(path.join(__dirname, '../package.json')).toString());
  if (!packageJson || !packageJson.engines || !packageJson.engines.vscode) {
  throw new Error('No vscode engine specified in package.json');
  }
  