Added some unary expressions
merge
Merge branch 'master' of https://gitlab.doc.ic.ac.uk/lab1314/wacc_37
TODO: Not done section of BackEnd.
working on if stat
working on if
merge
merge
working on if
merge
fixing branches
getting close to an implementation of strings, luke we have a dual label counter which should be fixed at some point and also the way that assign and declare were changed to have instructions is wrong with str which I will fix tomorrow
Merge branch 'master' of https://gitlab.doc.ic.ac.uk/lab1314/wacc_37

Conflicts:
	src/wacc/backend/BackEnd.java
tidying up if
boop
Merge branch 'master' of https://gitlab.doc.ic.ac.uk/lab1314/wacc_37
fixed nested if labels
working on while
merge Luke's changes
Merge branch 'master' of https://gitlab.doc.ic.ac.uk/lab1314/wacc_37