Improve auto-show/hide toolbar

[eranl]

1. Auto-show toolbar on any selection change/cursor move (if setting is on)
2. Only auto-hide toolbar while typing a word (if setting is on)

Should any of this be optional?

Mostly fixes #2281.

[Helium314]

Do the isResumed changes have any noticeable effects, other than for your use in LatinIME? It's used in Suggest, and I don't want to introduce any further bugs there.
Looks like "@return whether we started composing this word by resuming suggestion on an existing string" is incorrect with these changes.

[Helium314]

The difference of 1 is how you detect typing? If so, you should also consider that keys can input multiple characters, and this is not only for customized layouts, but normal for some languages.

[Helium314]

Should any of this be optional?

I suspect 2. might be unwanted for some users, so better make it optional. 1. should be fine I think.

[maruuk]

I think 1 should also be optional. If I type an incorrect word and autocorrect doesn't work, I click on it to select the correct one from the suggestion bar. After this change, I'll have to expand the suggestion bar, which will slow down my typing.

Btw, since you are improving the auto-show/hide toolbar, could you please take a look at these issues? #993 #1855