Bunch of mostly (cannot vouch) compatible changes

[tomjtoth]

Hello there,

I found your script and changed a few things according to my needs (I plan on firing this script up once a year, when I get warnings from MEGA about inactive accounts, replacing the need to log in to multiple accounts via the browser), feel free to modify the contents of, or reject this PR if you're uninterested!

Most notable changes

• added argument parsing for command line invocation
  • NOTE: functionalities accessed by args should probably also be exposed via a zenity dialog menu system
• less verbosity on command line, unless invoked with flags -v or --verbose
• more fluent instance creation dialog
• defaulting to MEGADIR=~/MEGA-Instances
  • no interference with a possibly "natively" running megasync process (not launched by this script)
  • possibility to override --megadir PATH_TO_OTHER_BATCH_OF_INSTANCES
  • --killall instances launched from MEGADIR (e.g. you can terminate batch A of instances without killing any of batch B or a "native" megasync process)
  • DEPATH now gets generated based on MEGADIR appending path as snake_case
• possibility to later add more instances to an already configured one
• convienence wrapper for --uninstall
• updated manual installation path to /usr/local/bin as /usr/bin should be managed by a distro's package manager (?)
• dependencies checked via loop
• [ -f "$MEGADIR/.configured" ] now represents the same as the previous FILE variable, only on a per-MEGADIR basis

[tomjtoth]

#7 should be handled by bbe4815 and 382a546

[tomjtoth]

#14 is also possible via the -a | --add-more flags somewhere in f0aa744

[tomjtoth]

#13 is possible via the -t | --toggle-autostart

#8 has (probably?) been fixed in 0adfd88