Patch and expose sift-jars

• the task replumb.boot-pack-source/sift-jars, an implementation of sift :add-jar that works on a set of jar strings, is now public
• the default for the target dir, to-dir, has been changed to a more suitable clj-src

A boot task for including source files

First release of the task replumb/pack-source:

• add custom :exclusions for avoiding dependencies
• add manual :deps option accepting additional dependency vectors
• expose replumb/rebase task for moving files with metadata
• add :include and :exclude regex for matching/not matching TmpFile paths