Fix bug with xaos interpolation, by setting all xaos values to zero first.

Remove unnecessary resize() in Interpolate().

These are from Simon Detheridge's PR:

Set file name padding in EmberRender and
EmberAnimate based on the log10() of how many images are getting rendered, rather than hardcoding it to 5.

Use non-locale-imbued stream for writing filename in EmberAnimate.

Properly cast immediate float value used with pow() in density filter kernel.

Source/Ember/Ember.h

@@ -981,7 +981,8 @@ public:
 		{
 			for (size_t i = 0; i < XformCount(); i++)
 			{
-				m_Xforms[i].SetXaos(i, 0);//First make each xform xaos array be maxXformCount elements long and set them to zero.
+				for (size_t k = 0; k < XformCount(); k++)//First make each xform xaos array be maxXformCount elements long and set them to zero.
+					m_Xforms[i].SetXaos(k, 0);
 
 				//Now fill them with interpolated values.
 				for (size_t j = 0; j < size; j++)//For each ember in the list.

Source/Ember/Interpolate.h

@@ -395,7 +395,6 @@ public:
 		vector<T> c(2);
 		Ember<T> localEmbers[4];
 		bool smoothFlag = false;
-		c.resize(2);
 
 		if (embers[0].m_Time >= time)
 		{