Generator Support

[ddmarshall]

Add capability to support specific generators. In particular

• Eclipse and CodeBlocks work better with no output message line breaks
• XCode needs certain compiler flags set in particular ways for the settings to make it into the project

[ddmarshall]

Here are some examples of needed additions:
if (APPLE)
set(ELI_CXX_FLAGS "${ELI_CXX_FLAGS} -stdlib=libc++")
endif()

if (CMAKE_GENERATOR STREQUAL "Xcode")
set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LANGUAGE_STANDARD "c++11")
set(CMAKE_XCODE_ATTRIBUTE_GCC_C_LANGUAGE_STANDARD "c99")
set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LIBRARY "libc++")
set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_INHIBIT_ALL_WARNINGS "YES")
set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_PEDANTIC "YES")
endif()