implemented testing environment and simple string drawing
now drawing by image
started to implement formula parsing
started to implement nested expressions. somethings still wrong here
bracket expressions now working
implemented bold, it, underline, overline
implemented line breaks
implemented ^
implemented subscript
implemented \~{}
implemented \arrow
implemented big and block
implemented renderIntervall
implemented intervall signs
implemented \frac
implemented matrix, cleaned
implemented \lim
implemented floor and ceil
implemented \root
implemented \interv