Add lightweight C++ STL

[mateoconlechuga]

Maybe we should add a small-ish STL so people can stop asking about it haha.

Although most of the time it is "why can't I #include " so not sure if this is even worth it.

[adriweb]

So apparently several of us have our eyes on https://github.com/electronicarts/EASTL

It's not so small, but i'm not sure this is really a huge problem.
License is OK, it's still decently active (much more than lots of other STLs at least), they mention "embedded systems" for example usages, and according to @runer112 "EASTL is kind of nice because it has all the normal STL stuff, but it also has more efficient containers if you want to seriously optimize".

I guess we should resume our efforts to try to make it work?

[adriweb]

( @runer112 as started the work of integrating EASTL in the https://github.com/CE-Programming/toolchain/tree/eastl-tice branch )

[adriweb]

In the meantime, Runer found this other one: https://github.com/embeddedartistry/libcpp

Which may be even better suited.