Adapt buttons in status bar according to context

[Ramsis-SNES]

With the recent font upgrade, the three dots in this line

text_spcload    .byt "Loading SPC data to SPC700...", 0

could be replaced like so:

text_spcload    .byt "Loading SPC data to SPC700", 127, 128, 0

Also, the status bar should adapt to the user's input:

• When the menu is opened, X:Menu should disappear.
• With an SPC playing, A:Select and X:Menu should disappear.

[mrehkopf]

SPC text is changed in v0.1.7, adaptive status bar isn't there yet.