MINOR: stats: improve compression stats reporting

Compression stats were not easy to read and could be confusing because
the saving ratio could be taken for global savings while it was only
relative to compressible input. Let's make that a bit clearer using
the new tooltips with a bit more details and also report the effective
ratio over all output bytes.
diff --git a/src/dumpstats.c b/src/dumpstats.c
index c8bdc2b..812f3d5 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -2827,12 +2827,22 @@
 
 		chunk_appendf(&trash,
 			      /* bytes:out + compression stats (via hover): comp_in, comp_out, comp_byp */
-		              "<td>%s%s<div class=tips>compression: in=%lld out=%lld bypassed=%lld savings=%d%%</div>%s</td>",
+		              "<td>%s%s<div class=tips><table class=det>"
+			      "<tr><th>Response bytes in:</th><td>%s</td></tr>"
+			      "<tr><th>Compression in:</th><td>%s</td></tr>"
+			      "<tr><th>Compression out:</th><td>%s</td><td>(%d%%)</td></tr>"
+			      "<tr><th>Compression bypass:</th><td>%s</td></tr>"
+			      "<tr><th>Total bytes saved:</th><td>%s</td><td>(%d%%)</td></tr>"
+			      "</table></div>%s</td>",
 		              (px->fe_counters.comp_in || px->fe_counters.comp_byp) ? "<u>":"",
 		              U2H(px->fe_counters.bytes_out),
-		              px->fe_counters.comp_in, px->fe_counters.comp_out, px->fe_counters.comp_byp,
-		              px->fe_counters.comp_in ?
-		              (int)((px->fe_counters.comp_in - px->fe_counters.comp_out)*100/px->fe_counters.comp_in) : 0,
+		              U2H(px->fe_counters.bytes_out),
+		              U2H(px->fe_counters.comp_in),
+			      U2H(px->fe_counters.comp_out),
+			      px->fe_counters.comp_in ? (int)(px->fe_counters.comp_out * 100 / px->fe_counters.comp_in) : 0,
+			      U2H(px->fe_counters.comp_byp),
+			      U2H(px->fe_counters.comp_in - px->fe_counters.comp_out),
+			      px->fe_counters.bytes_out ? (int)((px->fe_counters.comp_in - px->fe_counters.comp_out) * 100 / px->fe_counters.bytes_out) : 0,
 		              (px->fe_counters.comp_in || px->fe_counters.comp_byp) ? "</u>":"");
 
 		chunk_appendf(&trash,
@@ -3642,12 +3652,22 @@
 
 		chunk_appendf(&trash,
 			      /* bytes:out + compression stats (via hover): comp_in, comp_out, comp_byp */
-		              "<td>%s%s<div class=tips>compression: in=%lld out=%lld bypassed=%lld savings=%d%%</div>%s</td>",
+		              "<td>%s%s<div class=tips><table class=det>"
+			      "<tr><th>Response bytes in:</th><td>%s</td></tr>"
+			      "<tr><th>Compression in:</th><td>%s</td></tr>"
+			      "<tr><th>Compression out:</th><td>%s</td><td>(%d%%)</td></tr>"
+			      "<tr><th>Compression bypass:</th><td>%s</td></tr>"
+			      "<tr><th>Total bytes saved:</th><td>%s</td><td>(%d%%)</td></tr>"
+			      "</table></div>%s</td>",
 		              (px->be_counters.comp_in || px->be_counters.comp_byp) ? "<u>":"",
 		              U2H(px->be_counters.bytes_out),
-		              px->be_counters.comp_in, px->be_counters.comp_out, px->be_counters.comp_byp,
-		              px->be_counters.comp_in ?
-		              (int)((px->be_counters.comp_in - px->be_counters.comp_out)*100/px->be_counters.comp_in) : 0,
+		              U2H(px->be_counters.bytes_out),
+		              U2H(px->be_counters.comp_in),
+			      U2H(px->be_counters.comp_out),
+			      px->be_counters.comp_in ? (int)(px->be_counters.comp_out * 100 / px->be_counters.comp_in) : 0,
+			      U2H(px->be_counters.comp_byp),
+			      U2H(px->be_counters.comp_in - px->be_counters.comp_out),
+			      px->be_counters.bytes_out ? (int)((px->be_counters.comp_in - px->be_counters.comp_out) * 100 / px->be_counters.bytes_out) : 0,
 		              (px->be_counters.comp_in || px->be_counters.comp_byp) ? "</u>":"");
 
 		chunk_appendf(&trash,