CComponentsForm: add functions to get first and last item
CComponents: implement scroll functionality into CComponentsForm

CComponentsForm provides page scroll if found more
than one pre defined page and is working with all derivated sub classes from CComponentsForm .

Pages are defined with setPageNumber(0...n) in items (1st page = 0). The item page number property is
defined in variable cc_page_number. The highest page number sets the
count of pages inside container to required value. Thats compellingly!

To show a page, we can use setCurrentPage(0...n ) and paintCurPage() or use directly paintPage(0...n).
Note: global paint() will show the current page. Default page is 0 (as first).
Use setCurrentPage(0...n) to change this before first call of paint().
Note: In CComponentsWindow class, these methods are applied to window body.

For examples, take a look into CTestMenu
CChannelList: disable paint of clock background, it's not required here
gui/setting_helpers: use cAudio mixer interface
src/gui/components/cc_item_progressbar: change passive color to gray variant of active one
src/gui/components/cc_item_progressbar: simplify bitmap calculations
Merge remote-tracking branch 'martiis-neutrino-mp/master'

Conflicts:
	src/gui/audio_setup.cpp
	src/system/setting_helpers.cpp
	src/system/setting_helpers.h