Paging(fixed 50 items per page)

Added function to paging for each timeline.

* 50 items per page (fixed)
* placed **read more** link at the bottom of timeline if older message may exist

Fixed issues:

1. `oldestMessageDateTime` function doesn't work correctly
2. `createParameters` function changed `this._searchCondition` directly ( in other words, `this._searchCondition` will not be initial conditions(values))

Refactored several things.

1. Removed duplicated codes to apply effects for the message item when message was show, responded or removed.
2. Changed variables into literal

I will refactor in the future:

1. `var that = this` problem