Tim Chevalier 5a8ba073bc Make to_str pure and fix const parameters for str-mutating functions
Two separate changes that got intertwined (sorry):

Make to_str pure. Closes #3691

In str, change functions like push_char to take an &mut str instead of
an &str. Closes #3710
2012-10-11 14:17:59 -07:00
..
2012-10-04 19:59:47 -07:00