This branch introduces experimental support for long-format patterns (closes #43) in export. It is a major step towards introducing overabundance in downstream scripts.

So far, this has been implemented only for dynamic alignment. It makes the code much simpler in several aspects.

Checklist:

• @XachaB : do you think this approach is reasonable? Can I extend it everywhere?
• Add microclass computation
• Generalize to other pattern computations OR remove other pattern computations
• Use long format patterns in entry for entropy.
• Use long format patterns in entry for all scripts.
• Strong memory improvements with a categorical dtype for cell and lexeme (had some side effects: I needed to recreate merged columns in a better way, so I introduced a Paradigms class to handle this)

EDIT: removed useless dependency on #37.

EDIT 2: for the doc, the underlying data structure is now the following

lexeme,cell_x,form_x,cell_y,form_y,pattern
ab_11566,ill.pl,ɑˀ b ʒ i ,ela.pl,ɑˀ b ʃ t i ,[+voic] ⇌ [-voic]t / X+_i?
abbõnd_11569,ill.pl,ɑˀ bː i nʲ i ʒ ,ela.pl,ɑˀ bː i nʲ i s t ,ʒ ⇌ st / X+[-str -low -pre -tri]_
abbõndajāji_11570,ill.pl,ɑˀ bː ɯ n d ɑ j ɑː j i ʒ i z ,ela.pl,ɑˀ bː ɯ n d ɑ j ɑː j i ʒ i s t ,[+voic] ⇌ [-voic]t / X+_i?
abbõnz_11571,ill.pl,ɑˀ bː i nʲ i ʒ ,ela.pl,ɑˀ bː i nʲ i s t ,ʒ ⇌ st / X+[-str -low -pre -tri]_
abesīv_11573,ill.pl,ɑ b e sˑ i lʲ i ʒ ,ela.pl,ɑ b e sˑ i lʲ i s t ,ʒ ⇌ st / X+[-str -low -pre -tri]_
ābets_11574,ill.pl,ɑː b e t s i ʒ ,ela.pl,ɑː b e t s i s t ,ʒ ⇌ st / X+[-str -low -pre -tri]_

Almost everything relies on this single class. A column "applicable" can be added with the list of applicable patterns. Most often, x and y are unoriented, but for entropy, I duplicate the table and x corresponds to the predictor / y to the target.

It is incredibly easy to manipulate with groupby/apply, compared to the previous data structure.

When we store paradigms in non-human readable way, it looks like this:

form_x,form_y,pattern
1,3,s ⇌  / ssp_ <1>
5,7,s_ ⇌ _p / p_s_ <2>
8,10,s_ ⇌ _p / p_s_ <2>
18,11,None
1,13,ss_ ⇌ _s / _p_s <1>

Notice how we use the form_id to spare some memory by reducing redundant info (lexeme/cell)