Remove cpp98 mapping

[bernardnormier]

• [x] remove Ice for Ruby
• [x] clone the cpp "core" into cpp98 and update the build of cpp98-based language mappings (Python, PHP) to use cpp98
• [x] remove IcePatch2
• [ ] in cpp: port all services (IceGrid, IceStorm etc.) and associated tests to use ICE_CPP11_MAPPING
• [ ] in cpp: update slice2cpp to generate code only for the C++11 mapping, and remove all use of ICE_CPP11_MAPPING
• [ ] in cpp: replace all use of IceUtil::Thread, Mutex, Monitor by equivalent standard thread, mutex etc.
• [ ] port Ice for Python and Ice for PHP to the latest C++ mapping
• [ ] remove cpp98

[pepone]

Wondering it will be simpler to create a C++11 branch, and then:

• update slice2cpp to generate code only for the C++11 mapping, and remove all use of ICE_CPP11_MAPPING
• port all services (IceGrid, IceStorm etc.) and associated tests to use C++11 mapping, removing all uses ICE_CPP11_MAPPING macros
• port Ice for Python and Ice for PHP to the latest C++ mapping
• merge back to master

I don't see the benefice of creating a temporary cpp98

[bernardnormier]

I anticipate this step:

• [ ] port Ice for Python and Ice for PHP to the latest C++ mapping

won't start soon, as we want to refine the C++ API before starting it. Furthermore, the "port" of Ice for Python and Ice for PHP to the latest C++ will itself take a significant time as we plan to refactor these C++-based mappings to be more like Ice for Swift.

[bernardnormier]

We decided to keep the c++98 mapping and un-deprecate it.