Update changelog & authors

AUTHORS.txt

@@ -46,3 +46,7 @@ Jason Bishop <jason.bishop@bigassfans.com>
 matejcik <ja@matejcik.cz>
 Tobias Müller <Tobias_Mueller@twam.info>
 Jari Vetoniemi <mailroxas@gmail.com>
+Gabriel Staples <ercaguy@gmail.com>
+Amarnath <amarnath.h.96@gmail.com>
+Michal Rostecki <mrostecki@suse.de>
+Pei Wang <wangpei10@baidu.com>

CHANGELOG.txt

-nanopb-0.3.9.2 (2018-10-xx)
+nanopb-0.3.9.2 (2018-11-xx)
  Erroneous free() when using callbacks combined with PB_ENABLE_MALLOC (#346)
  Fix possible null-pointer dereference in decode_callback_field (#342)
  Fix FindNanopb.cmake on Windows (#335)
  Fix large generator memory usage with oneof fields (#338)
+ Fix error in splint test (#359)
+ Allow cmake to build as a shared library (#352, #353)
  Add --no-strip-path command line option (#326)
  Option for flattening nested protobuf names (#333)
- Fix dates in changelog (#329)
+ Documentation fixes (#329, #350, #358)
+ Better error messages (#351)
 
 nanopb-0.3.9.1 (2018-04-14)
  Fix handling of special characters in string/bytes default values (issue #322)