API CHANGE: cleanup of Common.xcs

Remove deprecated items. All are unused in the code.

since 2002 (ce44de00):

Gallery/ID_Dialog

Image/Color/PosterColor
Image/Color/RotationAngle
Image/Color/LeftRight
Image/Color/BlackWhiteThreshold
Image/Effect/MosaicX_Tile
Image/Effect/MosaicY_Tile
Image/Effect/SolarizationThreshold
Image/Effect/TileX_Tile
Image/Effect/TileY_Tile

since 2004 (f1e7d342):

OfficeObjects

since 2004 (2f137724):

ExternalApps/ExternalMailer/UseDefaultMailer
ExternalApps/ExternalMailer/CommandProfile
ExternalApps/ExternalMailer/Profiles

MailCommandLineProfile

since 2005 (c82714cc):

Path/Current/OfficeInstall
Path/Current/OfficeInstallURL

Change-Id: Ia6411ef0912096ced2dc7396e9636a09ee94714c