extension and cloudchat geared together to provide bookmarks and page visiting tracking.

1. when cloudchat connected to server, then it check bookmarks. If last upload day is
cloudchat.updateBookmarks.interval days before, then upload again. default is 10.
2. When extension starts, it'll monitor how user read the web page and takes score.
if the score is great than cloudchat.threshold.analyzeDoc (default 100), it starts
to analyze the document, if it's greater than cloudchat.threshold.reportVisiting (default 300),
it starts upload data.
3. expose converse.conn