Add line counter, rewrite positioning code and support real edge dodging, track number of grabbed strings in reader, don't grab from distance text nodes

reader.html

@@ -24,6 +24,7 @@ p
 </head>
 
 <body lang="ja">
+<p>Strings grabbed: <span id="linecount">0</span></p>
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 <div style="position:absolute;visibility:hidden"><textarea id="nazeka-paste-target"></textarea></div>