Add circuit support. In init.lua there are some examples of circuit elements.
Add other files to commit
Add more unstaged files
Remove delete m_circuit from ~ServerEnvironment
Fix segfault.

Segfault occured when new block generated (instead of loading from disk).
Edit swapNode().
Fix updateElement (create new states table).
Change updateElement() definition.
Fix some wire bugs.
Remove std::list<CircuitElement>::iterator from MapNode
Fix addElement() bug.
Add some comments.
Add documentation to lua_api.txt
Some style changes
Use tabs to indent
Remove word input repetition
Add support of multi-way wire.
Fix some bugs
Fix some bugs. Optimize for memory using
Merge conflict