add actions that control logging options

[cyrush]

Actions that control logging to give users more control than just params passed via ascent::open

Examples:

start logging at any time:

action: open_log # open ascent's logging
file_pattern: (support all params in new logging options added in #1426)

flush logs so they can be seen before ascent is closed out:

action: flush_log # flush current log streams to disk

stop logging and flush current logs:

action: close_log # close current log streams