closes #9, related to #7: no fixed DIV

Now you can click the button in the popup page!
I don't really know what caused my problem before....

Other modification:
* change name from "法令易讀器" to "法規亦毒氣"; old english name "zhLawEasyRead"
is gone from `manifest.json`, but I haven't decided yet whether to
retain it in cases that only english names are permittable.
* debugged #8 by modifying `ly.lci.js`; I misused
`document.location.pathname` to detect sub-string in search part.