It appears that java stack dumps contain the tab character. This causes
line length computation to be messed up, so (on at least some
terminals), the lines end up wrapping twice -- once when we hit the
right edge of the terminal, and then again a few characters later when
indent_wrap() inserts a newline. By using spaces, where pidcat and the
terminal can agree on the width of the character, we obviate this
problem.
