Add extra modes

[marcdeop]

This is a reduced version of #103

What this PR does:

New variable

Introduces extrakto_fzf_unset_default_opts in order to unset the environment variable FZF_DEFAULT_OPS.

I found out that certain operations would not work with my default FZF_DEFAULT_OPS value.

For example:
Having the option -1 (or --select-1) will make extracto's pop-up disappear immediately when there is 0 or just 1 match thus preventing you from switching to another filter.

Support other modes

Extra modes added:

• path
• url
• quote
• s-quote

Cosmetics

Add --word as a parameter for the sake of consistency.

How to try?

Before this PR:

set -g @extrakto_filter_order "url line quote s-quote word path all"

And no matter what you did, the filters would always be: word all line

Now calling extracto will give you the url filter as default as expected.

[laktak]

Thank you for your PR! I didn't know about FZF_DEFAULT_OPS causing side effects.

I reverted the changes to the extrakto.py since the -a option already let's you add custom filters.

[laktak]

Also you gave me the idea to use -a with user defined filters :)