Package the application

**Add package creation script (Issue #43)**

To package the application into a zip file, you will need to go to `/scripts/packaging.php`, and wait for 2 seconds.

The script copy all needed files/directories into `build` directory, then generate the file `dist/framadate-version-date.zip`, then delete directory `build`.

See merge request !48

* A new page is available on index, it allows user to send by mail all the polls created by a given mail address

Bug with admin name checking && Step 1 input radio aligment

- Passing from POST to GET some of the admin poll's modification buttons : remove vote, remove column, add column.
- Added create_poll.php a specific css file for the radio buttons aligment.
- Added some args to the poll's URL creation.

See merge request !50

Conflicts:
	app/classes/Framadate/Utils.php

	- Update composer.lock by the way
.