Add a bigger buffer for CoinLpIO to allow to store bigger names

Issue created by migration from Trac.

Original creator: @ycollet

Original creation time: 2014-03-10 09:05:24

CoinLpIO complains when name are longer than 100 chars.
You should either use string instead of chars to store names or use a ifdef to allow to fine tune the maximum size of the buffer like:

#ifndef COIN_LPIO_BUFFER
#define COIN_LPIO_BUFFER 1024
#endif

And use this symbol where the buffer is too small.