Tabs Aside 3.5

Changes:

• new sidebar active state indicator (issue #96)
• new variables for session title template (issue #95)

Bug fixes:

• creating a session via the tab context menu now uses the title template (issue #92)
• the position of a tab added to a session via the context menu is now consistent
• fixed a bug where the first tab of a restored session would rotate to the end (issue #98)