Delete obsolete files

	deleted:    nodes.h
	deleted:    tree.h
Implement DeclarationSpecifiers
Add automated bash test function t and tv

source util.h by `$ source util.sh` then t (test) and tv (test verbose)
will be available.
merged and fixed parser.y
added makefile to commit
more ast nodes yay
Start Node* subtypes for declaratoins
Merge branch 'master' of https://github.com/YutaMatsumoto/MIPSc
...
.
starting into ast statements