Place bundled SFML include paths before others

This allows to build with bundled SFML when system SFML (of another
version) is installed
Remove more dead and redundant code.
AudioCommon: Remove unused parameter from OpenSLESStream constructor
Merge pull request #987 from rohit-n/more-dead-code

Remove more dead and redundant code.
Merge pull request #989 from lioncash/param

AudioCommon: Remove unused parameter from OpenSLESStream constructor
Make Invalid instruction debug assert a non-debug assert.

Users need to be able to see this error message. Otherwise they can't
report bugs.
Merge pull request #992 from phire/betterassert

Make Invalid instruction debug assert a non-debug assert.
Merge pull request #841 from AMDmi3/bundled-smfl-include-order

Place bundled SFML include paths before others
GetOpInfo: Assert on all invalid Ops.

GetOpInfo was returning null pointers for invalid ops in subtables
instead of asserting an error. This was causing segfaults when the
jit tried to jit invalid code.
Merge pull request #993 from phire/fix_getOpInfo

GetOpInfo: Assert on all invalid Ops.
Merge branch 'master' of https://github.com/dolphin-emu/dolphin into VR-Hydra
Undo merged change to PPCTables.cpp which caused crashes.