Up the transfer timeout of small meshes to 120S. This matches

the change made for MAINT-2347.  Large transfers are still
10 minutes.  Add/update to-do list and add some more info to
the FAQ in the Readme.

indra/llcorehttp/README.Linden

@@ -653,4 +653,19 @@ HttpOperation::addAsReply: TRACE, ToReplyQueue, Handle:  086D3148
 
     Q2.  How's that data sharing with refcounts working for you?
 
-    A2.  Meh.
+    A2.  Meh.  It does reduce memory churn and the frequency at which
+    free blocks must be moved between threads.  But it's also a design
+    for static configuration and dynamic reconfiguration (not
+    requiring a restart) is favored.  Creating new options for every
+    request isn't too bad, it a sequence of "new, fill, request,
+    release" for each requested operation.  That in contrast to doing
+    the "new, fill, release" at startup.  The bad comes in getting at
+    the source data.  One rule in this work was "no new thread
+    problems."  And one source for those is pulling setting values out
+    of gSettings in threads.  None of that is thread safe though we
+    tend to get away with it.
+
+    Q3.  What needs to be done?
+
+    A3.  There's a To-Do list in _httpinternal.h.  It has both large
+    and small projects here if someone would like to try changes.

indra/llcorehttp/_httpinternal.h

@@ -66,6 +66,12 @@
 //   This won't help in the face of the router problems we've looked
 //   at, however.  Detect starvation due to UDP activity and provide
 //   feedback to it.
+// - Change the transfer timeout scheme.  We're less interested in
+//   absolute time, in most cases, than in continuous progress.
+// - Many of the policy class settings are currently applied to the
+//   entire class.  Some, like connection limits, would be better
+//   applied to each destination target making multiple targets
+//   independent.
 //
 // Integration to-do list
 // - LLTextureFetch still needs a major refactor.  The use of
@@ -75,7 +81,6 @@
 //   the main source file.
 // - Expand areas of usage eventually leading to the removal of LLCurl.
 //   Rough order of expansion:
-//   .  Mesh fetch [Underway]
 //   .  Avatar names
 //   .  Group membership lists
 //   .  Caps access in general

indra/newview/llmeshrepository.cpp

@@ -351,7 +351,7 @@ const S32 REQUEST2_HIGH_WATER_MAX = 80;
 const S32 REQUEST2_LOW_WATER_MIN = 16;
 const S32 REQUEST2_LOW_WATER_MAX = 40;
 const U32 LARGE_MESH_FETCH_THRESHOLD = 1U << 21;		// Size at which requests goes to narrow/slow queue
-const long SMALL_MESH_XFER_TIMEOUT = 60L;				// Seconds to complete xfer, small mesh downloads
+const long SMALL_MESH_XFER_TIMEOUT = 120L;				// Seconds to complete xfer, small mesh downloads
 const long LARGE_MESH_XFER_TIMEOUT = 600L;				// Seconds to complete xfer, large downloads
 
 // Maximum mesh version to support.  Three least significant digits are reserved for the minor version,