Plane: preparing for 2.68 release

Revert "Optimized APM_RC.InputCh() to prevent global interrupt disabl…

…e each time a value is read."

This reverts commit 6ef0652efa2f7b0bb7702f8abee4b54e5de3b20e.

This doesn't look safe to me. See my email to the list.

APM: prepare for 2.66