Thorough redesign of the LP/MIP interface (#44)

- Redesigned class structure
- Redesigned iterators
- Some functions in the basic interface redesigned
- More complete setting functions
- Ray retrieving functions
- Lot of improvements
- Cplex common env
- CLP macro definition to config.h.in
- Update lp.h to also use soplex and clp
- Remove default_solver_name
- New solverName() function in solvers
- Handle exceptions for MipCplex test
- Rename tolerance parameter to epsilon
- Rename MapIt to CoeffIt
- Lot of documentation improvements
- Various bugfixes

INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR})

LINK_DIRECTORIES(${CMAKE_BINARY_DIR}/lemon)

SET(DEMOS

  arg_parser_demo

  graph_to_eps_demo

  lgf_demo)

FOREACH(DEMO_NAME ${DEMOS})

  ADD_EXECUTABLE(${DEMO_NAME} ${DEMO_NAME}.cc)

  TARGET_LINK_LIBRARIES(${DEMO_NAME} lemon)

ENDFOREACH(DEMO_NAME)