Revert "Readd the old AXWii (rename the new version to NewAXWii) and set it as default"

Put back the new AX Wii as the default in this development branch.
AXWii: fix L/R channels being swapped when outputting audio samples
Handle 3ms at a time in AXWii instead of 3x1ms
Implement Wiimote sound mixing in AXWii
Implement low-pass voice filtering, untested because I couldn't find any game using it
Fix the voice LPF implementation
Better global volume adjustment on a voice. Fixes one of the 2 issues with the HOME button menu sound.
Implement AXWii command 01: ADD_TO_LR
Add polyphase resampling support in AX
Rewrite the linear interpolation SRC to give the exact same results as the one in AXWii
Merge branch 'master' into new-ax-hle
Update the right cur_addr_frac after wiimote audio resampling
Refactor the resampling code to avoid having two polyphase resampling implementations (normal/wm)
Add missing <functional> header include
OSX sucks at c++11
Fix audio glitching at the end of a voice because of bad non-looping sound handling in AXWii
Fix AUX volume mixing in AXWii: implement volume ramping and MixAdd properly. Home menu sounds now work properly.
Add volume ramping for MAIN output, separate old volume values for each AUX channel and refactor
Add an option to run the AX processing on the CPU thread. Fixes timing issues causing audio glitches on Wii, and should improve the overall stability of AX HLE.
Support loading polyphase resampling coeffs from User and Sys in HLE