Sections, SignPages: The key lists is now populated with only the user's own keys that he wants to get signed.
SignPages: Added a new page in the notebook: after user selects one of its own keys to be signed, this page will display informations about that key including UIDs, expiration date and signatures.
Merge branch 'develop' into gui

Conflicts:
	Sections.py
Merge branch 'gui' into network

Conflicts:
	Sections.py