Merge pull request #321 in G/fastr from ~ADAM.WELC_ORACLE.COM/fastr:feature/s4_generic_dispatch to master

* commit '4025133b':
  Corrected the name of a native method.

TestBase: suppress duplicate 'E'; move important method call from assert (in case assertions disabled)

Merge pull request #319 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:feature/updateformula to master

* commit 'cb814e73':
  updateform external implemented + tests

* commit '3ca5d6ef':
  Optimized sending environments through channels plus minor fixes to channels implementation.

* commit 'f3cd1289':
  "Dead" specializations detected by rbdiag
  rbdiag supports external builtins (no chimney-sweeping atm)

* commit 'f222f71e':
  Step towards replacing bzip2/xz compression with Java implementation

* commit 'c7f9ce54':
  Regenerated tests.
  Copy a shareable structure only if its attributes are modified before sending a message through the channel.
  Without a single method with test annotation source tests are not picked up for execution.
  Corrected name of internal FastR function.

unit tests: switch time zone to GMT as it is the default when java.util.TimeZone is dysfunctional; fix several tests with incorrect placement of 'na.rm=XX'; fix several syntax errors in tests

Copy a shareable structure only if its attributes are modified before sending a message through the channel.