Renaming spdy_sm usage to spdy_cs to conform with previous naming changes
Fixing build related to rename of spdy_sm_create
TS-2877: http_load waits until timeout when response body is zero
TS-2236: remove trailing null in response body set by fabricate_with_old_api

I'm seeing this too whenever a remap plugin set an error response
body using TSHttpTxnErrorBodySet.  I think the bug is simply failed
to realise that ink_bvsprintf will return resulting len including
the final null.
Bumped the version number for the 5.1.0 release
Bumped the version of the docs to 5.1 and 5.1.x
TS-2879: Remap errors and redirects should honor keep-alive
TS-2879: Remap errors and redirects should honor keep-alive
Added SPDY support, and some other minor cleanup
Doc: Plugin identity and related logging tags.
Undo the permit pinning change, amc objects
Fix Docs link.
Fix indentation from TS-1728
TS-2881: Redirection handling broken
Doc: jpeach suggested tweaks and amc tweaks.
TS-2632 Fixes to check the new configs properly
Adding small check for non-zero reads
TS-2766: Fixing missed string in URLImpl length calculation
TS-2880 Change the permissions on traffic.out to 0644
TS-2885 Change LuaJIT to build statically, and add --disable-luajit