Moved creation of MainPanel.scroll_frame to just above the creation of MainPanel.progress_bar

Moved creation of MainPanel.scroll_frame to just above the creation of MainPanel.progress_bar
Renamed MainPanel.close_button to MainPanel.xclose_button
ARL_CloseButton is now MainPanel.close_button - its creation was moved to the main file body from addon:InitializeFrame()
Moved ClosePopups() and ColourSkillLebel(), and all tooltip-related functions to just before the frame creation code.
Moved the icons in the filter menu more to the left so the text would fit in the panel.
Made various small syntax changes.