First commit of ScanSub thread and the accompanying policy object

Signed-off-by: arghdos <arghdos@users.noreply.github.com>
added couple of convience methods and updated the get_reddit method

Signed-off-by: arghdos <arghdos@users.noreply.github.com>
added a nifty clear_sub method (for the sake of testing)

better error checking on praw process creation

Signed-off-by: arghdos <arghdos@users.noreply.github.com>
more updates to the blacklist (can specify url or id directly to save a call to teh extractor)

Signed-off-by: arghdos <arghdos@users.noreply.github.com>
Added:
Approve post
xpost
Updated:
resolve_url

Signed-off-by: arghdos <arghdos@users.noreply.github.com>
updated test suite
Added:
test_approve_post
test_scan_sub
new database tests
test_xpost

Signed-off-by: arghdos <arghdos@users.noreply.github.com>