How could you say there is a standard convention ? This is absolutely false, just look at a few libraries and you will see it. Even in the industry, there isn't one.
Furthemore, it's only a matter of style, you can't say "this one is standard" just because the first lettre is lowercase instead of uppercase, this is stupid!
A believe a more intelligent proposition would be to follow the standard of each language(I mean the one use the standard library), for example C++ uses "foo_bar", C# uses "FooBar", Java uses "fooBar" ...