Merge pull request #63 from dreifachstein/master

Allow customization of component install dirs

Passed Travis CI.
Json::Value constructor: Accept any arithmetic type.
Improve comments on arithmetic type constructor and helper traits.
Make 64-bit int work with 'long int' and 'int64_t' for 64 bit builds (Issue #64)
Only use fix-width types for C++11 (Issue #64)
Json::Value constructor: Accept any arithmetic type.
Improve comments on arithmetic type constructor and helper traits.
Merge branch 'accept_all_arithmetic_types' of https://github.com/open-source-parsers/jsoncpp into accept_all_arithmetic_types
Merge branch 'accept_all_arithmetic_types'