Removed macros for C++11 code that is available on MSVC 2013.
Added modifiers to uri_builder that can clear certain components.
Fixed bug in clear member functions of uri_builder.
Added tests for empty username in the userinfo.
Merge pull request #49 from glynos/master

Added clear member functions  to uri_builder
Merge branch 'master' into hunter
Merge branch 'hunter' into travis.macosx