[TRAC] Clp no longer compiles using MSVC

[qtothec]

Moved from TRAC as part of COIN fORgery: https://projects.coin-or.org/Clp/ticket/62

Might be worth checking but Clp (1.15.5) no longer compiles with Visual Studio (2010 or 2012). Offending lines:

const int c0 = std::tolower(s0[i]);

which are lines 843 and 844 in CoinHelperFunctions?.hpp. VC++ doesn't know about std::tolower, not sure correct fix but dropping the namespace reference fixed it (i.e. just tolower()).