* Refactor edit one field dialogs to use validators and transfer data to and
from window functions.
* Add code to DIALOG_SHIM to handle validation and transfer functions since
the base dialog class code is not called by EndQuasiModal().
* Add custom validator class for filtering field text control characters.
* Add new field validator to edit schematic component dialog field text
control.
* Add new field validator to edit fields in library editor dialog field
text control.
* Make a few LIB_PART member functions const.
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.