Merge iostream fixes, mostly by Richard Smith.

Fixes #3612, #3311, #2094, #3010, #2894, #3011, #3352, #3505.


[SVN r58633]

libs/iostreams

@@ -1 +1 @@
-Subproject commit 70d3ec6d632670241a4270029762d9107f4ef77d
+Subproject commit a979898cb0c486867e6db11b84029360b7ed275f