Sketch implementaion of try_lexical_cast
try_lexical_cast is now implemented in optimal way
Applied improvements from `[boost] [conversion] try_lexical_cast` discussion: function is called try_lexical_convert and now uses perfect forwardings when possible.
Do forward input streamable parameter during lexical input streaming.
Added some tests for try_lexical_convert and fixed some issues.
Added docs for try_lexical_convert