Added a global home action when TeclaAccessibilityService connects.
Added methods to send global home and back actions.
Use global home and back actions on the HUD selections.
fixes #167
Fixes #169
Added methods to identify first and last scroll nodes.
Added scrolling on navigation.
set to perform scroll only if scroll is available.
Modified algorithm to allow highlighter to leave scrollable views.
Added scroll action when highlighter is outside of scrollable parent's view.
Added Tecla shield keyboard-based switch event detection.
Uncommented SwitchEvent receiver.
Made switch event provider available in TeclaAccesssibilityService.
Modified single-switch touch interface to use switch event provider.
Handled mapped actions for switch events.
Connected Tecla shield Switch E1 events to switch event provider.
Added switch E2	events to the switch event provider.
Modified SHIELDEVENT_TIMEOUT to send key only if one key is detected.
Added a TODO comment at the location of joystick switch detection.
Add build directory to hold development app builds for testing