Moved the ExpButtonText to the Constants section.

Moved the ExpButtonText to the Constants section.
Added MAINPANEL_NORMAL_WIDTH and MAINPANEL_EXPANDED_WIDTH.
Moved the acquire-type constants to the Constants section.
Moved the StaticPopup definitions to the Constants section.
Renamed factionHorde, factionAlliance, and factionNeutral to FACTION_HORDE, FACTION_ALLIANCE, and FACTION_NEUTRAL then moved them to the Constants section.
Moved various commonly-used local functions toward the top of the file.
addon.flyTexture is now MainPanel.filter_menu.texture
Moved creation of MainPanel.progress_bar from addon:InitializeFrame() to the main file body.
MainPanel:UpdateProgressBar() is now MainPanel.progress_bar:Update()
ARL_ResetButton is now MainPanel.filter_reset, and is created in the main file body instead of within addon:InitializeFrame()