Update HISTORY file for mzlib/class100 removal
optimizer repair related to use-before-defined

Don't optimize away a use-before-definition in an early compiler
pass. (More specifically, adjust the meaning of a flag within an
optimization helper function so that it works for decisions before the
letrec-fixing pass.)
adjust errortrace to record potential use-before-definition sites

Formerly, reference to a local variable could never raise an
exception.
fix use-before-definition bug in HtDP language implementation

Closes PR 14447
fix typo
typo
Add FAQ section
racket/draw Cocoa: fix surroate-pair patch for Pango
Mark class support as experimental in the TR docs

Please merge to v6.0.1
Demonstrate Racket/Datalog interop more and add unsyntax
Fix shapes with borders to work with pen styles.
Fix TR reference docs for `for`

Please merge to v6.0.1
repair props
fix initialization error
fix srcloc
have drdr ignore stderr that doesn't matter
increase pkg timeout
Minor fix for TR docs for `struct`

Please merge to v6.0.1
update correct answer for mac os x redex bitmap test
bring contract tests up to date with changes to undefined