make hourly Cron job quiet

otherwise, systems that are able to send mails would send the uninteresting output every hour to the admin

unmount tmpfs if RAM too small to prevent corruption of logdir

Log on disk wasn't copy on install, so the shutdown destroy everything.
#18 #17

It's maybe the pb of #17

source function not available into every /bin/sh

Added check of tmpfs size before syncing HDD to RAM.

Don't need the section "before" anymore.
Upgrade the license to a valid one.

Update service dependencies to start on early boot

This changes log2ram dependencies to start as early as possible, before other
services that may require access to /var/log, including rsyslog and
systemd-journald.

Additional dependencies on shutdown.target are required to ensure that
the service will be stopped at shutdown/reboot when DefaultDependencies
is set to "no" [1].

RequiresMountsFor declares dependency on /var mount when it is a mount point.

IgnoreOnIsolate prevents stopping the service when isolating another unit.

[1]: https://www.freedesktop.org/software/systemd/man/systemd.service.html

Remove log2ram log on startup.

Sync the ramlog back to disk, hourly.

* Write sync status to HDD_LOG/log2ram.log.

- Store sync status directly in the HDD log, to make sure we know
  about it if something fails.  This won't help if the HDD_LOG
  variable is borked, but it'll help with everything else.

- Made sync a function to avoid repeating five lines three times.

- log2ram now requires (cp or rsync) and tee, mount, umount.

* Split sync into syncFromDisk and syncToDisk.

- After restarting, I realized that I had combined both types of sync
  into one line, when the syncing failed.  This fixes that bug.

* Exclude log2ram.log from rsync so rsync doesn't delete it on sync.

- Since the cron job could be called before the user reboots after
  install (or if log2ram is disabled), we check that the hdd log
  location exists before syncing.

- Copy the log2ram.hourly sync script to cron's hourly directory on
  install.

- Store sync status directly in the HDD log, to make sure we know
  about it if something fails.  This won't help if the HDD_LOG
  variable is borked, but it'll help with everything else.

- Made sync a function to avoid repeating five lines three times.

- log2ram now requires (cp or rsync) and tee, mount, umount.

From @datenklause
With Type=oneshot, systemd waits until the start action has completed
before it considers the unit to be active, so dependencies start only
after the start action has succeeded. With Type=simple, dependencies
will start immediately after the start action has been dispatched.

thank hardvk0 from armbian forum

no x flag for logr2ram.server

The name of the mount point is now log2ram

Move "Before" to "[Unit]"

Update README.md to correct path to log2ram

This tweak is required to make it run under Ubuntu 16.04