minor improvements to the readme

Added logrotate support

install: Fixing code typo

The last bracket shall not be glued to the directory.

The actual code is generating a runtime error like the following :
 erwan@raspberrypi:~/download/log2ram $ sudo ./install.sh
 Created symlink /etc/systemd/system/sysinit.target.wants/log2ram.service → /etc/systemd/system/log2ram.service.
 ./install.sh: 19: [: missing ]
 ##### Reboot to activate log2ram #####

This patch simply adds the missing space to make this script work.

Improved readability of the readme and comment in the config file

Added:
- check on install
- clear old folder on install
- better uninstall script
- use systemctl instead of manually call script in the cron

This reverts commit 4479c11a41.

use rm -f instead of rm

Suppresses an error message, if the file does not exist.

The init is useless and the mount was async.

Update uninstall.sh

Fix typo on line 9

As asked into #23 #21

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.