Gui keys

[diveshuttam]

Basic GUI key commands added.
There are many improvements possible. I have added some as TODOs.
@dashohoxha if you have some more issues in mind (except #91) please add comments about them in this PR only and I'll address them with other improvements.
closes #88

[dashohoxha]

Divesh, first of all I am satisfied that you continue to work even after the official end of GSoC. However your studies should have higher priority now than this project, so feel free to dedicate more time to your studies.

I have looked at your commits and I have noticed a few small problems (for example you often forget to declare local variables with local). If you make a quick review of your code trying to fix such problems, it would be great.

I like that you add a #TODO comment where you think it can be improved but you are not sure how. If you can create an issue that contains a list of TODO marks and references to them, this might be useful for me or someone else that may want to fix some of them.

I will have to test carefully the existing application and look at the code, in order to be able to make any suggestions for improvements. However usually it is easier to just fix something rather than suggesting you to fix it. I hope to find some time for doing this.

Another thing is that I would like to migrate the project to GitLab, but without disrupting your work. This will also need to update the URL of the project on wiki pages, man page, README, etc. something that you have done previously as well. So, when you are ready, let's merge gnupg-2.2-gui to gnupg-2.2 and after that do the migration.

Also, let's not forget to add to EasyGnuPG the work that you have done already about nautilus scripts:
https://github.com/diveshuttam/EGPG-tasks/tree/master/nautilus-egpg/nautilus-scripts

I cannot think of any other tasks for the time being.

[dashohoxha]

I think that details should be declared as local. In some cases this does not make any difference, but it is a good habit and a good practice to declare local variables as local.

[diveshuttam]

Sorry, I have been a bit busy for past two days. I am free today and will address the issues by tonight.

[diveshuttam]

I have looked at your commits and I have noticed a few small problems (for example you often forget to declare local variables with local). If you make a quick review of your code trying to fix such problems, it would be great.

I have done the local thing

Another thing is that I would like to migrate the project to GitLab, but without disrupting your work. This will also need to update the URL of the project on wiki pages, man page, README, etc. something that you have done previously as well. So, when you are ready, let's merge gnupg-2.2-gui to gnupg-2.2 and after that do the migration.

It will not be able to find time for a couple of more weeks. I can do this after that. By that time can we merge this to the gnupg-2.2-gui branch and test it.
Of course gnupg2.2 and gnupg2.1 branches are working fine for now so I don't think gui part should be merged until it is tested significantly.

Also you can migrate this project to gitlab now only, I can take out time to make the necessary updates to gnupg2.2 and gnupg2.1 branches as they are minimal. For this gnupg-2.2-gui branch I will resume once I am sorted with other things (mostly towards end of this month).

Also since Gitlab allows import of Github projects, which imports issues as well; I guess I can continue to work on this part on Gitlab without much disruption.