For vm-display-fbdev, add primitive access to TAP_START_TIMEOUT and TAP_END_TIMEOUT

[marceltaeumel]

As discussed here in this pull request:

• Framebuffer input-handling improvements #737

See https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/Cog/platforms/unix/vm-display-fbdev/sqUnixEvdevKeyMouse.c

#define TAP_START_TIMEOUT 0.18
#define TAP_END_TIMEOUT 0.3