Deprecated a few methods

  * `TangUtils` should be provided by Tang, not REEF
  * `EnvironmentUtils.addAll()` should be provided by Tang
  * `EnvironmentUtils.getReefHome()` makes no sense any more, given that REEF isn't assumed to be "installed"
  * `EnvironmentUtils.getClassLocationFile()` was never used and is merely a shorthand for JDK functionality.
  * Deprecated `EnvironmentUtils.getVersion()` in favor of `REEF.getVersion()`