Autocompleter not sharing the same client pool

[filipecosta90]

@gkorland @MeirShpilraien we should refactor this and remove:

// NewAutocompleter creates a new Autocompleter with the given host and key name
func NewAutocompleter(addr, name string) *Autocompleter

Autocompleter should only have:

// Autocompleter implements a redisearch auto-completer API
type Autocompleter struct {
	name string
}

instead of the current:

// Autocompleter implements a redisearch auto-completer API
type Autocompleter struct {
	pool *redis.Pool
	name string
}

[filipecosta90]

this issue is fixed by #36 with the method
func NewAutocompleterFromPool(pool *redis.Pool, name string) *Autocompleter

[filipecosta90]

solved by #36