* Support hierarchic menus
This introduces a new menu engine implemented in the class CUIMenu,
which can be configured with C-tables. This should make it easier to
extend the menus, without modifying the code too much. The UI provides
a main menu, which selects the TG to be edited and a TG sub-menu, which
presents the already known TG parameters (voice bank, voice, volume,
pan, detune and channel). A sub-menu is entered with single click and
left with double click. There are arrows displayed on the LCD, which
show the direction(s), to which the knob can be moved. All TG related
parameters are maintained in the class CMiniDexed now.
* uimenu: Make the tables const
* uimenu: Add sub-menu "Edit Voice"
Menu items can be re-sorted, if necessary.
* uimenu: Add "Reverb" sub-menu
* Map reverb float parameters to range 0 .. 99
* minidexed: Add global (non-TG) parameters
* minidexed: Protect reverb module with spin lock