[webkit-dev] Coding Style addition - `using namespace` positioning

[Brady Eidson]

This morning a fellow engineer asked us what our standard is on where  
`using namespace` statements should go.

I had a strong feeling there was "a right answer", but was dismayed to  
see it wasn't in the coding style guidelines, and also to see how  
inconsistent we are throughout WebKit.

This morning I filed https://bugs.webkit.org/show_bug.cgi?id=29499 and  
included my proposal for the new guideline.

If you have time and could take a look at https://bug-29499-attachments.webkit.org/attachment.cgi?id=39771 
, please let me know if there's any objects or suggested changes to my  
proposal.

Thanks,
~Brady