Fix left-out ambiguities on sind, cosd, acosd.

Avoid confusion with functions from Intel C compiler.
Add the missing using declaration.

Author: pavoljuhas

src/diffpy/srreal/Lattice.cpp

@@ -52,6 +52,7 @@ void Lattice::setLatPar(double a0, double b0, double c0,
 {
     using diffpy::mathutils::cosd;
     using diffpy::mathutils::sind;
+    using diffpy::mathutils::acosd;
     ma = a0;
     mb = b0;
     mc = c0;

src/diffpy/srreal/PointsInSphere.cpp

@@ -43,7 +43,8 @@ LatticeParameters::LatticeParameters( double _a, double _b, double _c,
 
 void LatticeParameters::update()
 {
-    using namespace diffpy::mathutils;
+    using diffpy::mathutils::cosd;
+    using diffpy::mathutils::sind;
     ca = cosd(alpha); cb = cosd(beta); cg = cosd(gamma);
     sa = sind(alpha); sb = sind(beta); sg = sind(gamma);
     // Vunit is a volume of unit cell with a=b=c=1