add function for logarithmus to base 2 for convenience

src/logarithmus.c

@@ -15,6 +15,10 @@ double logDec(double a){
     return logX(10.0, a);
 }
 
+double logBin(double a){
+    return logX(2.0, a);
+}
+
 double logN(double x, double eps){
     if(x <= 0){
         return -1.0;