Initialisation du plugin epub en copiant le plugin squelette
Fix position of buttons in menu of fleaditlater plugin
Revert "Fix position of buttons in menu of fleaditlater plugin", bad evaluated solution.

This reverts commit 369db3795350d5ed8464eef8aaf7dca1a32c38ee.
Fix button position in fleaditlater menu (due to float position)
Replace spaces with tabs in one line.
Remove license (not clear now, it depends on Leed and PHPePub)
Create base of epub_plugin_action. Need still lot of work.
Create simple menu to download files.
Add constants and variable to create .epub file.
Prepare functions to manage settings (don't know if we'll use them, so commented)
Adjust example plugin function and comment not needed ones.
Add PHPePub as submodule for the epub plugin.
Fix include path.
Adjust constants and remove global variable.
Remove finally unused code and files.
Modify epub menu to add choice to download text only or full articles.
Add createEpub function inspired by PHPePub 2.50 example.
Add TODOs
Add License and update links
Remove use of git-submodule.