fix scalar definition into exp list (related to glayzzle#532)

Merge branch 'master' of https://github.com/glayzzle/php-parser

publish 3.0.0-prerelease.7

bump prerelease version

update ignore list

release 3.0.0-alpha2

pre-release 3.0.0-alpha1