Add Objective-C/C++ and Java to code formatter script; format those files. (#755)

* Allow format_code to format .m/.mm files; clang-format already knows how. * Run format_code.py on all objective-c/objective-c++ files. * Add Java file extensions to format_code.py * Format all Java source files. * Remove check for objc header, as they are now supported. * Format objective-c .h files. * Don't let lint comment on line length any more; code formatting will report that.

Author: jonsimantov

admob/src_java/com/google/firebase/admob/internal/cpp/AdRequestHelper.java

@@ -25,7 +25,6 @@
  * into their (typically more complicated) Java equivalents.
  */
 public class AdRequestHelper {
-
  public AdRequestHelper() {}
 
  /**