Currently, if a old label already containing a '/' (or a space) is edited, it is accepted,
but no new not allowed char can be added to the label.
(Previously, a sheet pin label was not filtered)
Setfocus now works on macos dialogs by setting DLGSHIM_USE_SETFOCUS.
This option is only enabled __WXMAC__ is defined.
FixOSXCancelButtonIssue() is now called inside DIALOG_SHIM::SHOW.
All other calls from within the dialogs were removed.
File "rules" has instructional text as comments near top.
2) Convert all text files in repo to LF line ending form.
Any checkout done with "rules" in play will convert the working
tree to native line ending, while keeping repo as LF line ending.