Optimize windowHints, make "char" immutable with hack the function of "hs.hints.addWindow"

[cxdongjack]

the immutable hotkeys is more efficient than random ones

char generation algorithm as below:

• try to find char in user specific dict, like { ['com.sublimetext.3'] = 'S' }
• parse the bundleID to single char, like com.apple.Terminal -> 'T', bundleID is stable than title
• loop the charhints(i.e ABC..XYZ), find the nil char in 'dict'

other optimized points:

• try to use only one key against the 'vimperator' style
• seperate the imutable with the random, random ones use the numbers
• fix the annoying problem, chars are changed when window be bring to frontend

here is the code in my config https://github.com/cxdongjack/hammerspoon/blob/master/jump.lua#L30

hope some help

[cxdongjack]

The hotkey is the the first char of the application name with your intuition.

[cmsj]

I think this is an interesting idea, and I just opened #1388 suggesting that we rewrite hs.hints to be a pure Lua module using hs.canvas and hs.windowfilter.

Fancy taking a crack at it? :D