added Makefile for proj3
added Vagrantfile for proj3
added beginning test file for a list type
added beginning test file for stack type
updated git ignore file
removed old list test file
removed old stack test file
updated makefile
added new stack header, implementation and test files
renamed stack header and implementation to not collide with stdlib stack
updated makefile
edited stack and test files to not collide with stdlib stack
edited function signatures to take pointers
added tests for push and pop