Seashell offline mode released.

Now able to compile and run C code while disconnected from the websocket connection.

Local storage used to store user files persistently offline.

Local file storage synchronized with backend filesystem when connection is reestablished.

Able to run tests while offline.

seashell-cli can generate LLVM bytecode files compatible with Seashell (to be used in place of object files).

Integrate the seashell-clang-js library (Offline compilation depends on this repo being built and installed correctly alongside Seashell).