Add Project Euler problem #63 Dlang solution

pe-0063/dub.json

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+{
+	"description": "Project Euler #63 - D Solution",
+	"name": "pe-0063"
+}

pe-0063/source/app.d

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+// Powerful Digit Counts
+// https://projecteuler.net/problem=63
+
+import std.stdio;
+import std.datetime.stopwatch;
+import std.math;
+
+void main() {
+     auto timer = StopWatch(AutoStart.yes);
+
+    int totalCount = 0;
+
+    foreach (i; 1 .. 10) {
+        real log_i = log10(cast(real)i);
+        int count = cast(int) floor(1.0 / (1.0 - log_i));
+
+        totalCount += count;
+    }
+
+    timer.stop();
+
+    writefln("\nProject Euler #63\nAnswer: %s", totalCount);
+    writefln("Elapsed time: %s milliseconds.\n", timer.peek.total!"msecs"());
+}