Changes suggested by Olav.

Some misspelling in all.
Modelling_tools:
	- Better description of state and transitions
	- Add example to Tecla chapter explaining quantifiers
Changes suggested by Olav.

Model 1:
	- Clarify what a static predicate is.
	- Add two static constraints onto the railway graph.
	- Fix the wrong definition of the switch blocks;
		"a leg of a switch is not unique (as there are two)".
Change suggested by Olav.

Defining static predicate in the model 1 chapter.
Removing "static predicate" and "dynamic predicate"
categorizations in the appendices as I have no proof
that the predicates are in fact "static"/"dynamic".
Changes suggested by Olav.

Analysis of model 1:
	Altered the section about proof obligations to
	make it clearer.
Old changes (suggested by Olav and Lars-Henrik).