update: loading screen

1 add flag isLoading, 
2 disable button when isLoading
3 change demo button methord
update: loading screen ui 

progress text update as programe runs
update: demoMode button clicked prepare panels with init data
commit b4 switch to connection check branch
added: BaseAtivity which has flags and a method to check device
connectivity.
update: other activities extends BaseActivity
add: isDemo Flag for BaseActivity
update: 1 check connection for activities when onCreate;

2 PanelListFragment refreshStatus(boolean isDemo, boolean isConnected)
takes 2 args now.