model: post-processor preparations

This includes:
 - support for paralell data access
 - foreachCommit ()
 - foreachBug ()
 - getCategories ()
 - getComponents ()
 - getSeverities ()
 - getStatuses ()
 - getPriorities ()
 - getProjects ()
 - getComments ()
 - getBugHistory ()
 - exception cleanups
Add initial post-processor infrastructure
git-miner/model: Collect file stats
svn-miner: is (): accept log files and svn repositories
git-miner: implement stop ()
miner: add support for miner specific settings
miner: turn MetaData into a class
miner: move Miner.MetaData to MetaData
miner: Add parameter helpers
git-miner: add option "process-diffs"
bugzilla-miner: add option "process-comments"
bugzilla-miner: add option "process-history"
bugzilla-miner: add option "pass-size"
bugzilla-miner: add option "page-size"
miner: add progress api
git-miner: track progress
bugzilla-miner: track progress
git-miner: log empty lines (+,-)