[Libreoffice] Remove "using namespace ::rtl"

[Julien Nabet]

Hello,

I finished the removing of "using namespace ::rtl" except in binfilters. 
(there were no compilation pb with my Linux env, hope it's the case with 
Windows and Mac envs).
Even if binfilters is going to be "extracted" from LO, doesn't it worth 
to purge "using namespace ::rtl" from it (I think about the people 
who'll take care of this) ?

Julien.