While a backup or restore task was running, the status_line property
would be updated for each file processed.
Meanwhile, the gui (BackupBox, for example) was periodically
accessing the status_line property to set a label.
Without protection, the gui was picking up garbage from status_line
instead of the filename, and was flooding output with markup warnings.
There was probably potential for a crash as well.
Changing to available_bytes instead of calculating the free bytes from (size_bytes - used_bytes) respects potential reserved space for "for root only" e.g. on ext4 file systems. It should prevent running out of space in the unfavorable cases having the timeshift archive located on the actual root file system.
Restored calculation and display, which was deleted in commit 8d77b18f.
However, the behavior has been changed slightly:
* We try to determine the sizes using `btrfs qgroup show`
* This is only successful on systems with enabled qgroups
* If so, we enable the columns
* Otherwise, we hide them
I did not restore the methods for enabling quota.
But I restored destroying qgroups on snapshot removal.
This also fixes a bug, I encountered on a system with enabled qgroups:
Since the removal of the now restored behavior, I encountered lots of 0.00B qgroups,
because they seem to have been created all along, but they have no longer been removed:
```
$ sudo btrfs qgroup show .
qgroupid rfer excl
-------- ---- ----
0/5 92.00KiB 92.00KiB
0/262 4.00GiB 4.00GiB
0/798 135.20GiB 334.31MiB
0/799 14.07GiB 254.51MiB
0/1657 0.00B 0.00B
0/1658 0.00B 0.00B
0/1665 0.00B 0.00B
0/1666 0.00B 0.00B
0/1691 0.00B 0.00B
0/1692 0.00B 0.00B
0/1721 0.00B 0.00B
0/1722 0.00B 0.00B
0/1723 0.00B 0.00B
0/1724 0.00B 0.00B
0/1727 0.00B 0.00B
…
```
There used to be a installer file with ".run" extension that could be executed on any Linux distribution to install Timeshift. This method of installing Timeshift is no longer available or supported since many years.
Also remove the config file for generating the installer.
This seems to be an issue with glib2 2.74 and strings that contain a improper unicode escape code (\uXX instead of /uXXXX). Since this function is used by all the progress windows, creating or deleting snapshots from the GUI was causing a crash.