How to remove duplicate rows from matrix

I want to remove duplicate rows from a matrix. I read How can I remove duplicates in an array but keep the same order?, but this is not exactly what I want.

The solution above removes duplicate values (cells) from matrix (and returns a vector), but I need to remove duplicate rows and return a matrix — the same matrix without duplicate rows.

Example:

a = [1,2; 3,4; 5,6; 1,2; 7,8]

a =
     1     2
     3     4
     5     6
     1     2
     7     8

%...

ans =
     1     2
     3     4
     5     6
     7     8

The order doesn't matter.