Removed deprecated color literals in the root namespace.

Deprecated in 52f2d297ca (April 2016), but
never actually causing any warning, so very annoying to deal with.
Explicitly call `using namespace Math::Literals;` instead.

doc/changelog.dox

@@ -170,6 +170,9 @@ See also:
 -   Removed @ref Platform application constructors taking @cpp nullptr @ce,
     deprecated in June 2016 for windowless apps and in March 2017 for windowed
     apps. Use constructors taking the @ref NoCreate tag instead.
+-   Removed availability of @ref Math::Color3 and @ref Math::Color4 literals in
+    the root namespace, deprecated since April 2016. Explicitly call
+    @cpp using namespace Math::Literals; @ce instead.
 
 @section changelog-2018-10 2018.10
 

src/Magnum/Magnum.h

@@ -51,15 +51,6 @@ namespace Magnum {
 namespace Math {
     #ifndef DOXYGEN_GENERATING_OUTPUT
     template<class> struct Constants;
-
-    #ifdef MAGNUM_BUILD_DEPRECATED
-    namespace Literals {
-        constexpr Rad<Double> operator "" _rad(long double);
-        constexpr Deg<Double> operator "" _deg(long double);
-        constexpr Rad<Float> operator "" _radf(long double);
-        constexpr Deg<Float> operator "" _degf(long double);
-    }
-    #endif
     #endif
 }
 
@@ -710,13 +701,6 @@ typedef Math::Frustum<Double> Frustumd;
 
 /*@}*/
 
-#ifdef MAGNUM_BUILD_DEPRECATED
-using Math::Literals::operator "" _deg;
-using Math::Literals::operator "" _rad;
-using Math::Literals::operator "" _degf;
-using Math::Literals::operator "" _radf;
-#endif
-
 #ifndef DOXYGEN_GENERATING_OUTPUT
 template<UnsignedInt, class T> class Array;
 template<class T> class Array1D;