defcustom to set the trigrams path

[humitos]

I added a new defcustom to be able to customize the trigrams directory. By default, it uses the one where the library is installed.

Let me know any comment, please.

Thank you!

[tmalsburg]

Hi, thanks for the PR. Can I ask why you need this feature?

[humitos]

Yeah. Maybe it's very specific to my own (strange) configuration. I don't know, but I will explain it here so you can decide what to do.

My setup is like this (~/.emacs.d):

...
├── startup.d
│   ├── 01git-gutter.el
│   ├── 02flyspell.el.disabled
│   ├── 99material-theme.el
│   ├── ace-jump-mode.el
│   ├── any-ini-mode.el
│   ├── auto-complete.el.disabled
...
...
├── packages
│   ├── ace-jump-mode.el -> ../vendor/ace-jump-mode/ace-jump-mode.el
│   ├── ace-jump-mode.elc
│   ├── any-ini-mode.el -> ../vendor/any-ini-mode/any-ini-mode.el
│   ├── any-ini-mode.elc
│   ├── apiwrap.el -> ../vendor/apiwrap.el/apiwrap.el
│   ├── apiwrap.elc
│   ├── async.el -> ../vendor/emacs-async/async.el
│   ├── async.elc
│   ├── autopair.el -> ../vendor/autopair/autopair.el
│   ├── autopair.elc
│   ├── avy.el -> ../vendor/avy/avy.el
│   ├── avy.elc
│   ├── browse-at-remote.el -> ../vendor/browse-at-remote/browse-at-remote.el
│   ├── browse-at-remote.elc
...
...
└── vendor
    ├── ace-jump-mode
    ├── any-ini-mode
    ├── apiwrap.el
    ├── autopair
    ├── avy
    ├── browse-at-remote
    ├── buftra.el
    ├── company-mode
...
...

• startup.d contains all my own configuration for a specific plugin
• packages contains symlinks to the libraries that I want to load at startup (in the load-path variable)
• vendor contains all the external plugins/libraries as git submodule

So, as this plugins is looking for trigrams folder at the same path that the .el file, it fails. Two solutions:

1. create a symlink to trigrams also from packages
2. allow the plugin to configure the path of trigrams

As I thought that this should be something configurable because this same issue could affect other people, I wrote the PR.

Now, you know the background and can judge by yourself :)

[tmalsburg]

Sure, we can add this. Thanks for the PR.

[humitos]

Thank you so much. I appreciate it :)