Refactor writing and deleting cache

Should be safe from race conditions an exception now
Save timestamp when removing component cache entry

Simplifies Api
Make Kwf_Component_Cache_Mysql_Test runnable when no memcache is installed
Use string as microtime

To support 32bit systems because integer of timestamp+milliseconds is too large
Get microseconds correctly also when start with 0
Do not track when kwcPreview is enabled
Return timestamp, not masked timestamp
Merge pull request #119 from fraxachun/3.4-viewcache-delete

Refactor writing and deleting cache

Should be safe from race conditions and exceptions now
Merge remote branch 'github/3.4' into 3.4
update update action to convert also parent_subroot_id correctly
Merge branch '3.4' into 3.5

Conflicts:
	Kwf/Component/Cache/Memory.php
	Kwf/Component/Cache/Mysql.php
Use correct comparison operators everywhere
Merge remote branch 'github/3.5' into 3.5
used correct column in videoPlayer form
Fix wrong default behaviour for analytics opt out
changed _curModule to kwf_controller_action_welcome

is necessary because kwf can run now in subfolder