SlingboxLib: Fix alternative CSlingbox constructor

CSlingbox::CSlingbox(const char * szAddress, unsigned int uiPort /* = 5001 */) {
  // Call default constructor
  CSlingbox();
  ...
}

"CSlingbox();" - object is created and immediately removed.
Therefore with CSlingbox(const char * szAddress, unsigned int uiPort /* = 5001 */) class members will not be initialized.
[pvr] fix unnecessary creation of new CPVRChannel instances
[builtin] fix activatewindow if directory path differs

After #5081 the built-in "activatewindow" does not work if you stay for example in the video window and you want to activate the same window with a different path.
This fixes the issue by comparing the directory path of the current active window with the given directory path of activatewindow.
Respect parent path decision when cleaning paths.

When cleaning the video library and a source containing TV shows was unavailable,
choosing to keep it only kept the source root, while subdirectories were
removed.
The result was that TV shows "disappeared".

This is fixed by checking if there's a decision for the parent path when
cleaning the path table.
[configure] libflac is not a hard dependency now
[linux] - update docs/README.*
Merge pull request #5282 from maksqwe/slingboxlib_fix

SlingboxLib: Fix alternative CSlingbox constructor
[slingbox] add .patch file after b3d686357d0912ce8c748bc013c93b0b6a47cd9b
Merge pull request #5527 from stefansaraev/flac

dont require libflac to build kodi core
dxva: fix selection of render target format
[keyboardlayouts] add Turkish
[vfs] Fix reading with zero size and null pointer
[vfs] Fix write with zero size and null pointer
[emu] Better emulate system read()/fread() functions
Merge pull request #5532 from queeup/keyboardlayouts

[keyboardlayouts] add Turkish
[vfs] PosixFile::Write(): remove unneeded cast
Merge pull request #5534 from Karlson2k/fix_vfs_and_emu_01

Better emulate system read() and fread() functions, fixes #15490
[rebrand][darwin/rebrand] - adapt readmes
[rebrand][packaging/seatbeltunlock] - renamed seatbeltunlock to be appnameagnostic, fix the pkg, make it org.xbmc.kodi-seatbeltunlock use @APP_NAME@
[rebrand][packaging/osx/ios/atv2] - move all package scripts to appname
agnostic folders, rename them to be appname agnostic and use @APP_NAME@ -
also add migration step in debian post-inst which will move XBMC data to Kodi if found