Update bin/changelog.js to handle merge commits not in Github's default format
Update bin/changelog.js to handle merge commits not in Github's default format

The current version of the script looks for commits with the text "Merged #XXXXX from someones/branch"
to determine if a PR was merged. This PR changes the script to additionally handle merge commits (ones
with two parents) that are in the format of "normal commit message (#XXXXX)".

It also fixes the sorting of PRs so that duplicated ones are grouped together.

mfeckie/ember.js,GavinJoyce/ember.js,cibernox/ember.js,cibernox/ember.js,stefanpenner/ember.js,givanse/ember.js,emberjs/ember.js,miguelcobain/ember.js,knownasilya/ember.js,givanse/ember.js,elwayman02/ember.js,stefanpenner/ember.js,sly7-7/ember.js,GavinJoyce/ember.js,mfeckie/ember.js,cibernox/ember.js,GavinJoyce/ember.js,tildeio/ember.js,miguelcobain/ember.js,intercom/ember.js,sandstrom/ember.js,sandstrom/ember.js,elwayman02/ember.js,miguelcobain/ember.js,tildeio/ember.js,fpauser/ember.js,fpauser/ember.js,intercom/ember.js,mfeckie/ember.js,mixonic/ember.js,mixonic/ember.js,knownasilya/ember.js,tildeio/ember.js,stefanpenner/ember.js,cibernox/ember.js,asakusuma/ember.js,asakusuma/ember.js,GavinJoyce/ember.js,emberjs/ember.js,asakusuma/ember.js,intercom/ember.js,givanse/ember.js,knownasilya/ember.js,sly7-7/ember.js,sandstrom/ember.js,fpauser/ember.js,fpauser/ember.js,elwayman02/ember.js,asakusuma/ember.js,mixonic/ember.js,mfeckie/ember.js,miguelcobain/ember.js,givanse/ember.js,sly7-7/ember.js,emberjs/ember.js,elwayman02/ember.js,intercom/ember.js