added perfect forwarding ctor to boost::flyweight
avoided -Wshadow warnings
fixed interferences between rvalue ref compiler support and perfect fwd ctor and used move semantics where possible to the extent that the library now --unofficially-- supports move-only key_type's and value_type's
refactored perfect fwd / rvalue ref scaffolding
added experimental std::initializer_list support
removed erroneous test case
mended erroneous test case
correctly documented construction from value_type as explicit
documented initializer list support
fixed error in previous fix
Merge branch 'develop'