Added new session feature for HSTS (#79).

The main stuff for the new session feature to handle HTTP strict Transport
Security is added.
Use SoupDate instead gint64 to store the expires at (#79).
Load and save hsts whitelist from file (#79).
Merge branch 'master' into feature/hsts
Fixed wrong url in status bar if hsts changed uri (#79).

This is a workaround for a missbehaviour in webkit. If the URI is changed
within the request-queued scope of the soup session, the changes are not
reflected if the URI is taken from webkit_web_view_get_uri(). Event if the
page is fully loaded webkit assumes to be on the wrong URI, but the
webinspector shows the right one.
Moved cookiejar session feature into own file (#79).
Removed no more needed session.c.

The two remaining function are moved into main.c.
Merge branch 'feature/hsts'

Conflicts:
	config.mk