import mongodb 2.2.2 from branch reallyenglish
USES=compiler:gcc-c++11-lib for C++11 issue

the default compiler on 10.0 and later is clang but mongodb 2.2.x does
not support clang (2.4.x does). as we are not going to upgrade our
cluster, we will stick to 2.2 for a while.
https://github.com/Homebrew/homebrew/issues/22771

also,
    - use new style lib$FOO.so (required by the latest bsd.port.mk)
    - USES=scons instead of USE_SCONS (not supported any more)
    - add CONFLICTS
    - add NO_STAGE
fix wrong lib name in SConstruct
replace hardcoded optimizations level with CFLAGS
use `|' as separator

the CFLAGS contains slashes.
use bandled boost lib

- lots of s/"foo.h"/<foo.h>/ to make it clear than they are system libs
- remove third_party/pcre and snappy to avoid confusion
- remove patch-tools__tool.cpp and patch-boost-1.52 because they make it
difficult to patch many files
- try fixing linker errors but failed