Remove the unused menu bar and status bar from alsoft-config
Update the period size/count sliders when loading
Disable HRTF remove button when no files selected
Don't have ../../ as part of the target name
Limit the source step to 10

This means the combination of the buffer frequency, source pitch, and
doppler shift can't exceed 10x the device playback frequency.

This is needed to keep the mixer from starving with a really high
increment, causing small DstBufferSize values that require a lot of
iterations.
Use OpenAL_SOURCE_DIR for the CMake module path and declare the project earlier

The minimum CMake version required is also bumped to 2.6. Patch by Andrew West,
allows OpenAL Soft to be properly built as a sub-project.
Some .ui changes that Qt Designer insists on