Add forgotten modules to std.package.

Author: berni44

std/package.d

@@ -58,6 +58,7 @@ public import
  std.net.curl,
  std.net.isemail,
  std.numeric,
+ std.outbuffer,
  std.parallelism,
  std.path,
  std.process,
@@ -69,9 +70,11 @@ public import
  std.stdint,
  std.stdio,
  std.string,
+ std.sumtype,
  std.system,
  std.traits,
  std.typecons,
+ std.typetuple,
  std.uni,
  std.uri,
  std.utf,