[confluence] replace subtitle flag icons with new ones

As discussed in #3552, this replace the subtitle flag icons with new
32x32 pixel icons from https://www.gosquared.com/resources/flag-icons/

This also fixes some wrong flags like uk. It's Ukrainian not United
Kingdom.
videodb: SQL query cosmetics in CleanDatabase()
videodb: use faster (NOT) EXISTS instead of (NOT) IN CleanDatabase()
videodb: handle files whose source is completely gone differently during clean
[confluence] texture changes for epg timeline view
CRegExp::PrivateRegFind: fix incorrect order of arguments in log
[addons] don't set dependencies not met when the broken tag is set in the repo
[addons] don't attempt to auto-update add-ons that don't have dependencies met
[xmlutils] validate dates before writing them to XML
read/write dateadded uisng XMLUtils
Merge pull request #3722 from jmarshallnz/no_nagging

No nagging of broken add-ons
Merge pull request #3736 from jmarshallnz/xml_date_time

Only write dates/date times to XML if they're valid - fixes #14159
FIX: [droid] proper mouse buttons handling
Merge pull request #3739 from koying/fixdroidmousebuttons

FIX: [droid] proper mouse buttons handling
[release] version bump to 13.0 alpha11 as we start new merge window
fix crash loading JPEGs where m_cinfo.scale_num was set to 9 due to not finding a suitably sized scale factor. Thanks to tscheck
Merge pull request #3708 from Montellese/videodb_clean_offline

videodb: better support for sources being temporarily offline during a library clean
context menu: move "Remove from library" to "Manage..." sub menu
context menu: use string-based media type detection instead of VIDEO_DB_CONTENT_FOO
context menu: add Manage... sub-menu to movie sets