Remove rows or columns of a matrix : delrows delcols

delrows (resp delcols) removes one or several rows (resp columns) of a matrix.
delrows (resp delcols) takes 2 arguments : a matrix A, and an interval n₁..n₂.
delrows (resp delcols) returns the matrix where the rows (resp columns) of index from n₁ to n₂ of A are removed.
Input :

delrows([[1,2,3],[4,5,6],[7,8,9]],1..1)

Output :

[[1,2,3],[7,8,9]]

Input :

delrows([[1,2,3],[4,5,6],[7,8,9]],0..1)

Output :

[[7,8,9]]

Input :

delcols([[1,2,3],[4,5,6],[7,8,9]],1..1)

Output :

[[1,3],[4,6],[7,9]]

Input :

delcols([[1,2,3],[4,5,6],[7,8,9]],0..1)

Output :

[[3],[6],[9]]