[LyX/master] Add missing using declarations

[Georg Baum]

commit c4613963faa4bb03dbb5e42b419c8f82e3e6d2d8
Author: Georg Baum <b...@lyx.org>
Date:   Sun Dec 21 19:05:00 2014 +0100

    Add missing using declarations
    
    This fixes using std::tr1::regex for non-MSVC compilers.

diff --git a/src/support/regex.h b/src/support/regex.h
index 125befc..96d6836 100644
--- a/src/support/regex.h
+++ b/src/support/regex.h
@@ -62,6 +62,11 @@ namespace lyx {
 #    define match_partial match_default
 #  endif
 #  define LR_NS std::tr1
+namespace lyx {
+using LR_NS::regex;
+using LR_NS::regex_match;
+using LR_NS::sregex_iterator;
+}
 #else 
 #  include <boost/regex.hpp>
 #  define LR_NS boost