Also allows you to have modules in mongos and the shell, as well as mongod.
Requires changes to the modules, to have SConscript files, and define libraries.
Allows modules to have unit tests, interesting linking rules, dependencies into
mongo, etc.
Still may need to do some work on includes. The mongo-enterprise module has very
simple include requirements, today.
This patch does the following:
1.) Remove pcre.h dependencies in the C++ client, and remove some other
unnecessary dependencies.
2.) Clean up how we build the client from the client source tarball, so it's
more like how we build it from the git repo / full source tarball.
3.) Fix up our "scons" so you only have to write "scons ." to build all of our
binaries, the binary archive (zip or tgz) and client source archive (zip or
tgz).
4.) Fix up SCons aliases "core", "tools", and "all".
5.) Let user specify the name of the client tarball via a SCons command line
switch.
Resolves SERVER-4231, SERVER-5255.
