Periodically execute calendar sync

[a-t-0]

      <p>Write a cronjob that executes the following commands for tasks with projects:</p>

0. Browse to the folder with calendar synchronization files.

cd ~/maintenance/gCal/

1.a Loop through all tasks
1.b Identify/list all projects, (e.g. uni.int.as and uni.int.ex as different projects).
1.c Loop through list with all projects
1.d Assign the project (name) as tag to all tasks in that project.

task status:pending proj:uni.int modify +uni.int
task status:pending proj:uni.rep modify +uni.rep

2. Then sync all tasks with (google) calendar using the tags to calendars.
   2.a Note, distinguish calendars up to 2 dots in the project name. E.g. both tasks uni.int.as and uni.int.ex go into a (new) calendar named: TW uni.int.
   ./tw_gcal_sync -c "TW intern" -t "uni.int"
   ./tw_gcal_sync -c "TW represInterac" -t "uni.rep"

3. If you want you can expand this method by asking the user whether they want custom calendar names e.g. TW intern in stead of `TW uni.int`.