less: total cleanup and bugfix.

less: total cleanup and bugfix.
Doesn't die horribly on binary files anymore.
In fact, they _100%_ work now. Control chars
are in reverse video, including DEL and that idiocy of VT-10x,
Meta-ESC [inventor of which should be prohibited from reproducing].
Regex search is fixed also. When you specify search ('/' key),
control chars turn into dots (unhighlighted),
and found occurrences highlighted instead. This is reversible.
Memory management fixed (was leaky as hell) and optimized.
Linewrapping fixed and thoroughly tested.
Max buffer size made configurable.
~ 600 bytes saved.