Extract history from Scrapy repository

[dangra]

Per scrapy/scrapy#1007 (comment) we want to retain commit messages, dates and authors of selectors history as developed in Scrapy repo

[dangra]

I pushed the changes extracted by the following script to master branch (still under review)

git filter-branch -f --prune-empty \
  --index-filter "git ls-files | grep -Eve '(selector|xpath)' | xargs git rm --cached"

# http://jimmy.schementi.com/splitting-up-a-git-repo/
tmpfile=$(mktemp -t splitgit.XXXXX)
trap "rm $tmpfile" EXIT
cat >$tmpfile <<!
#!/usr/bin/env ruby
old_parents = gets.chomp.gsub("-p ", " ")
new_parents = old_parents.empty? ? [] : \`git show-branch --independent #{old_parents}\`.split
puts new_parents.map{|p| "-p " + p}.join(" ")
!
chmod 755 $tmpfile
git filter-branch -f --prune-empty --parent-filter $tmpfile HEAD

Only rest moving file around and preparing a proper python packaging for selectors once we decide the name.

[dangra]

This is in master branch now.