OPDS: refactored unit test and fixed a minor bug with undefined image_rel
Merge pull request #1312 from Frenzie/master

OPDS: refactored unit test and fixed a minor bug with undefined image_rel
Merge pull request #1310 from hwhw/master

fixes for scrolling, fix for double-refresh, misc stuff
make coverage in after_success stage
So that if the coverage job is timeout it won't fail the
CI result.
fix coverage test fails on OPDS browser module
for some reason luxl.lua has problem when being set hook for luacov
fix #1175
Merge pull request #1314 from chrox/master

make coverage in after_success stage
small change of UIManager:show(): No more automatic refresh

This eliminates the API difference between the extra parameters of
UIManager:show() and setDirty(). They work the same now.
Note that this also eliminates the automatic refresh that took place
before when using show() without refresh options. It always refreshed
the full screen, which led to too big refresh regions all over the
place. Thus, refresh has now explicitly to be asked for, hopefully
encouraging to implement it in the widget that gets shown (and is
aware about the screen region it covers).

Also add an event that is triggered when a widget is closed:
CloseWidget. So a widget can implement "onCloseWidget()" to trigger
actions upon closing - most commonly, this is a refresh for the area
previously taken by the widget. That way, the widget's user does not
have to take measures to ensure that the area is refreshed later.
clean up refreshes

This is a larger clean-up of the refresh situation.
The general shift is that refreshes are now mainly triggered by
the (top-level) widgets when they get shown or closed via UIManager.

All refreshes for the widgets when they are in use were handled by
themselves before. This adds the case of showing/closing.

It is the desired result of not having UIManager:show()/:close()
do (full screen) refreshes on its own.