Additionally: the tests against GnuR externals now check the result
of the external call as opposed to checking the result of the wrapper
of the external call. This helps to find even tinier differences.

* commit 'c15ae475':
  A fix to vector update to preserve types in case when no actual modification happens.
  Fixed a problem with handling .Environment attribute.

Merge pull request #323 in G/fastr from ~MICK.JORDAN_ORACLE.COM/fastr:feature/apache-compress to master

* commit '67ecb276':
  Use xz internal for RCompression.lzmaUncompressFromFile

* commit '958935b4':
  ci.hocon: add Mac gate

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.

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.

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

* commit '115405bc':
  Handle GNU R timeouts (e.g a crash) during unit test generation

* commit '5d94d5f0':
  checkstyle fix
  refactor context creation/initialization to match TruffleLanguage createContext/initializeContext

Merge pull request #308 in G/fastr from ~ADAM.WELC_ORACLE.COM/fastr:feature/rstudio_integration to master

* commit '7cbefa14':
  Used more appropriate API call to retrive a path from source section.
  Temporary fix for on-demand source section generation.
  Minor fix to functions returning contexts.

Merge pull request #307 in G/fastr from ~ADAM.WELC_ORACLE.COM/fastr:feature/various_updates to master

* commit 'f196abf3':
  Fixes to the parse builtin.

* commit '00136165':
  add comment
  fix regression in embedded mode polyglot init

* commit '3ecc7ef3':
  Fix new invalid fallback handlers.