TS-2504: replace OpenSSL detection with AX_CHECK_OPENSSL

Use the ax_check_openssl.m4 macro from the autoconf archive so that
we don't need to carry around custom OpenSSL detection logic.
TS-2504: detect OpenSSL library in 64 bit library paths
TS-2504: fix bad OpenSSL lib64 detection patch merge
TS-2305: fall back to ftruncate on posix_fallocate failure
TS-2505 Add --offline to traffic_line
TS-2521: add stub for hacking documentation
TS-1668: Updated the documentation for HSTS
Reorder the build subdirs, such that all code compiles first
TS-2419: Don't close client connection when responding with a 204 and
there is no body - Fixed a bug when the 204 is served by cache
Reorder the build subdirs, such that all code compiles first
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/trafficserver
Add parans to fix build error with -Wall from commit a5c00b225
Add parans to the _right_ place to fix build with -Wall
Cleanup some dead code from Log.cc
TS-2425: Update to TS-2261 for loading plugins as root
TS-2525: Remove restriction on outbound transparency with SSL.
TS-2526: remove the g_stats_snap_fpath global variable
TS-2481 Incorrect origin server port used sometimes (with keep-alive).
Fix typo in traffic_shell
s/and/an/