SAOC 2020 Milestone 3 Week 4

[Robert Aron]

Update for week 4 of Milestone 3

Last week I managed to do the following tasks for #SAOC2020:
- finished the interface for GDrive library
- added models for gcalendar library


The plan for the next milestone:
- test the gdrive library
- finish the gcalendar library
- test the gcalendar library
- (maybe) start the implementation for gmail

Milestone 1 updates: [0]
Milestone 2 week 1: [1]
Milestone 2 week 2: [2]
Milestone 2 week 3: [3]
Milestone 2 week 4: [4]
Milestone 3 week 1: [5]
Milestone 3 week 2: [6]
Milestone 3 week 3: [7]

[0]: 
https://forum.dlang.org/post/eaefvlbgikujonfjjzqi@forum.dlang.org
[1]: 
https://forum.dlang.org/post/jezqwzpeknpxhmqgkewe@forum.dlang.org
[2]: 
https://forum.dlang.org/post/kffvsmmxrkftxlbqklsd@forum.dlang.org
[3]: 
https://forum.dlang.org/post/yvbnsycuxqjfxghqajbu@forum.dlang.org
[4]: 
https://forum.dlang.org/post/jwasbvtjbofftybnsqro@forum.dlang.org
[5]: 
https://forum.dlang.org/post/gimihhnxzbkeodvrotoy@forum.dlang.org
[6]: 
https://forum.dlang.org/post/qfpwiuyojozzkvdfkive@forum.dlang.org
[7]: 
https://forum.dlang.org/post/rdnvyqmmfqnvjwsmfbzx@forum.dlang.org