Update LICENSE text to 2015, implement a checker that validates
whether a 2014 or 2015 version of the license is on each {.c,.cc,.h} file.
Fix the ones that are missing it.

Allows us to collect profiles of the open source build using gprof.

-) Detecting system and embedded presence of zlib and OpenSSL with ALPN.
-) Automatically disabling secure targets if no OpenSSL present
--> make all won't work if no OpenSSL is present, forcing the users to select the nonsecure Makefile targets explicitely.
-) Removing build instructions for OpenSSL - this isn't really necessary anymore.
-) Adding more blurb about OpenSSL and the new Makefile features.
	Change on 2014/12/12 by nnoble <nnoble@google.com>
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82020890