Finish a2tip for ahk2

[ewerybody]

I found the previously tt and now a2tip functions suuper useful and used them all the time to implement easy feedback to the user.
With ahk2 there was quite some changes and I put off fixing a2tip and just patched it so that it pops a static tooltip that at least removes itself as before. But the mouse following was not yet in and the font stuff. And ...

• re-implement mouse follow
• implement a2tip config variables
• create a2tip_example tool
• repair font selection
• implement a2ui settings for all the a2tip config variables
• implement timeout estimation based on msg length
• add a2tip customizations to example tool