Log BerkeleyDB version at startup

Prints the actual version of BerkeleyDB that is linked against, if
wallet support is enabled.

Useful for troubleshooting.

For example:

    2014-05-01 07:44:02 Using BerkeleyDB version Berkeley DB 4.8.30: (April 9, 2010)

    2014-05-01 07:54:25 Using BerkeleyDB version Berkeley DB 5.1.29: (October 25, 20 11)
Update build instructions for Berkeley DB

- People were having problems with the .so when installing in
  alternative locations.
  Like gitian, build a static library with -fPIC that can
  be embedded into the executables.

- Add some missing steps

- Add reminder that BerkeleyDB is only needed when wallet support is
  enabled
Removed LevelDB changes

Syntax Highlighting
Merge pull request #4114

bfb154e Update build instructions for Berkeley DB (Wladimir J. van der Laan)
d0a2e2e Log BerkeleyDB version at startup (Wladimir J. van der Laan)
stop bitcoind/bitcoin-cli processes that might have been left running
Merge pull request #4074

d3081fa Removed LevelDB changes (super3)
reorder includes to compile on OpenBSD

From getifaddr(3) manual:
"If both <net/if.h> and <ifaddrs.h> are being
included, <net/if.h> must be included before <ifaddrs.h>"

http://www.openbsd.org/cgi-bin/man.cgi?query=getifaddrs&apropos=0&sektion=0&manpath=OpenBSD+Current&arch=i386&format=html
Merge pull request #4119

2364b11 reorder includes to compile on OpenBSD (Fabian Raetz)
don't use sed's -i option to stay posix compliant

POSIX does not define sed's -i option. To stay as portable
as possible we should not relay on it.
doc: remove specific mention of boost 1.55

There is no need to use any specific version of boost on Linux/Unix.
Even 1.37 should still work.

Also the mention of boost-dev doesn't belong after adding oldstable.
Remove it. libboost-all-dev is already mentioned earlier.
Merge pull request #4120

dbe8f75 don't use sed's -i option to stay posix compliant (Fabian Raetz)