Don't load clojars cert in default project map.
Don't add all files in git vcs commit. Fixes #1558.
Put a newline in between META-INF/services/ entries.

Refs #1561.
Document how to use bundled clojars.pem in case of CA problems.

Refs #1053.
Write pom.properties in :prep-tasks, not during jar creation.
Document pom.properties.

[ci skip]
Merge remote-tracking branch 'upstream/master'