Use glib to get portable mode dir

This should fix any non-ascii paths
Fix using negative index
xtext: Add word and line selection modes

Similar to a GtkTextView if you double click you enter word selection mode
and if you triple click you enter line selection mode.
Allowing you to drag and select more than a single character.

Closes #1108
Fix DOMAIN and EMAIL patterns.

Closes #1107
Escape values set via pluginpref

Fixes #790
Merge branch 'master' of https://github.com/hexchat/hexchat