Add WIP compile_node and symbol_table modules.

10_11_jack_compiler/jackcompiler/compiler/compile_node.py
	-Add a module that will contain functions to compile various
	`parser.ParseTreeNode`s.
	-Currently contains the following such functions:
	`_compile_varDec()`/`_compile_classVarDec()`.

10_11_jack_compiler/jackcompiler/compiler/symbol_table.py
	-Add a module with a `SymbolTable` class, which allows variable
	management.