[OE_BP need for XB-018fab2] Changes required to apply backported patches. Simply moves flags off the Open call so they can be updated.

Signed-off-by: Stephan Raue <stephan@openelec.tv>
[OE_BP XB-018fab2] Optionally allow caching for all network streams, including those on LAN (via new advanced setting 'alwaysforcebuffer')
[OE_BP PR3104] Use advancedsetting to speed up ReadRate in players