remove obsolete files
add Deref
add DriveGet SpaceFree
update Performance.htm
update #SingleInstance
add page for colour chart
update WinGetText
repurpose IfWinActive.htm for WinActive()
repurpose IfWinExist.htm for WinExist()
update #Warn
remove #NoEnv (update references to env vars)
remove AutoTrim
DriveSpaceFree -> DriveGet Var, SpaceFree
remove EnvAdd/Sub/Mult/Div; add DateAdd/Diff
remove FileReadLine
remove obsolete IFs and String commands
rename String*.htm to Str*.htm (except StringCaseSense)
rename String* commands to Str* (except StringCaseSense)
remove Progress, SplashImage and SplashTextOn/Off
remove SetBatchLines