Add removeResult method; change name of setResult
Add remove{Test,Student} methods; match Student
Refactor inputting & var. names; add removeTest

Added utility methods for getting (+ve) integers & lines.

Using `badInput` ocer `! inRange`, because it seems more readable.

Changed something in the table formatting (???) -- think I reverted
something I did before.
Merge branch 'master' of https://github.com/raehik/testStore

Conflicts:
	TestDatabase.java
	TestInterfaceCli.java

Merged Charlie's setResultOfStudent changes and my removeTest/
removeStudent methods. A few other changes were made.

Changed '&' to '&&' in setResultOfStudent -- latter is 'lazy' (or
'bitwise'?).