You should use this uri to access your library :
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<%@ taglib prefix="comtags" uri="comtags" %>
We need to use tagdir while using tagfiles. but as you deploy your tagfiles as a jar within lib folder, you have to use "uri" attribute corresponde to the <uri></uri> element of the TLD file.
Moreover as Cristophe already mentions it. you need to put these files in the META-INF (TLD files AND tag files) folder wirhin simpleTag.jar file. Every .jar has its own META-INF folder inside it.