doc: Add historical release notes

Add all known release notes for versions since 0.3.12,
thanks to Matt Corallo for collecting them on the wiki.

doc/release-notes/release-notes-0.6.2.md

@@ -0,0 +1,50 @@
+Bitcoin version 0.6.2 is now available for download at:
+http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.6.2/
+
+This is a bug-fix and code-cleanup release, with no major new features.
+
+Please report bugs using the github issue tracker at:
+https://github.com/bitcoin/bitcoin/issues
+
+
+NOTABLE CHANGES
+
+Much faster shutdowns. However, the blkindex.dat file is no longer
+portable to different data directories by default. If you need a
+portable blkindex.dat file then run with the new -detachdb=1 option
+or the "Detach databases at shutdown" GUI preference.
+
+Fixed https://github.com/bitcoin/bitcoin/issues/1065, a bug that
+could cause long-running nodes to crash.
+
+Mac and Windows binaries are compiled against OpenSSL 1.0.1b (Linux
+binaries are dynamically linked to the version of OpenSSL on the system).
+
+
+CHANGE SUMMARY
+
+Use 'git shortlog --no-merges v0.6.0..' for a summary of this release.
+
+Source codebase changes:
+- Many source code cleanups and warnings fixes.  Close to building with -Wall
+- Locking overhaul, and several minor locking fixes
+- Several source code portability fixes, e.g. FreeBSD
+
+JSON-RPC interface changes:
+- addmultisigaddress enabled for mainnet (previously only enabled for testnet)
+
+Network protocol changes:
+- protocol version 60001
+- added nonce value to "ping" message (BIP 31)
+- added new "pong" message (BIP 31)
+
+Backend storage changes:
+- Less redundant database flushing, especially during initial block download
+- Shutdown improvements (see above)
+
+Qt user interface:
+- minor URI handling improvements
+- progressbar improvements
+- error handling improvements (show message box rather than console exception,
+etc.)
+- by popular request, make 4th bar of connection icon green