Merge pull request #183 in G/fastr from ~MICK.JORDAN_ORACLE.COM/fastr:feature/ffi to master

* commit '92c8708a': (157 commits)
  buffer bug fix in Rembedded.c
  Add TruffleBoundary to JNI native down calls
  Suppress Solaris build for embedded app test
  Suppressed embedded test build for Solaris
  checkstyle/copyright fixes
  FFI: Refactor native array handling to be correct wrt nested calls
  RFFIUtils: add call death to tracing; use unbuffered stream
  JNI_CallRFFI: use synchronized to allow nested calls
  Add a test for nested FFI calls
  call System.gc in R gc
  ffi tracing; handle case where native side enabled, jaa side not
  Refactor log file handling for embedded mode, tagging log files with pid. Invoke R_Suicide in embedded mode rather than return to console.
  Remove command options that are handled by shell
  Introduced new native functions and fixed implementation of some others.
  Moved a flag determining browser mode to context.
  Added a new opaque type to represent contexts.
  Refactor R_GlobalContext as method call to VM
  FFI tracing: trace JNI side to same file FD as Java side in embedded mode
  Fixed a problem with strsplit function.
  Record embedded mode early in RContext; only trace native calls to file in embedded mode.
  ...