Added total and partial functions as well as let expressions
Added total and partial functions as well as let expressions

jjdekker/libminizinc,nathanielbaxter/libminizinc,nathanielbaxter/libminizinc,nathanielbaxter/libminizinc,tias/libminizinc,tias/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc,jjdekker/libminizinc,jjdekker/libminizinc