feat(ast05): start assignment 5
feat(ast05): add designed classes

Class Member contains information for a single member.
Class MembershipList contains list of all members and implements an
interface for user commands.
Class Tester interact with user and tests MembershipList
feat(BinarySearchTree): implement methods, format code.

Implemented methods: size(), contains(), findMinimum(), getHeight(),
toString()
Also code is now formatted
style(BinaryTreeBasis): proper format + add @Override
feat(TreeNode): add toString() + format code

Added method toString() and helper prepareString()
chore(project.properties): change main class for project
feat(Tester): move user iteraction outside list iteraction methods
fix(TreeNode): change spaces to variable for printing
feat(answers): add answers on the last question in pdf
fix(Tester): add trim for lines entered by user, remove unused import
docs(ast05): add header and method comments