#119: fix restart bugs and old-style cycling anchors

This fixes anchor handling for the old-style Daily, Monthly, etc cyclers.

This also fixes picking up the correct initial cycle point from a state file
and also clarifies some of the naming - it gets confusing when we are
either storing cycle points as strings or as objects, or moving between
the two.

This also fixes a problem with the runahead pool change where tasks
beyond the stop point are no longer present in the state file on
stop-point-based suite shutdown. This stalls particular suites. The
restart and state-dump tests have been changed to reflect the
state-file/db alteration.

This also adds an initial cycle point option for "cylc validate", for
use when an initial cycle point has not been specified in the suite.rc
file.

@hjoliver, please review.