Remove: pgqadm and related code, its unmaintained

Although it was nice to have Python code that shows
how PgQ ticker and maintenance operations should work,
if it's unmaintaned, it's pointless.
skytools.Config: New default variables.

config_dir - directory where config is located at
config_file - config file itself.
Merge remote-tracking branch 'petr/master'
Londiste: fix trigger generation when extra params that are add-table specific are used (introduced in commit 364ade9)