Fixed a bug in parenthesis_around_minus (latex_translator.py). Had not made a exception for if the string started with a -, which caused a error.
Fixed a bug in parenthesis_around_minus (latex_translator.py). Had not made a exception for if the string started with a -, which caused a error.

MathGen/oppgavegenerator,w0pke/oppgavegenerator,MathGen/oppgavegenerator,w0pke/oppgavegenerator,MathGen/oppgavegenerator,w0pke/oppgavegenerator