Added sendmail_app and sendmail_template to config

sendmail_app and sendmail_template were not configurable
before. Added them to Mailer.from_settings and make list
of sendmail_template. Added to doc and tests as well.
Added .idea to .gitignore
Set version to 0.13-hp
Reverted version change
Removed .idea from .gitignore
Imports of asbool and aslist on seperate lines
Clarify expected value.
Changelog for PR#52.