* resource.h: Add new field IDC_CHOOSE_INST_TEXT. Modify

* resource.h: Add new field IDC_CHOOSE_INST_TEXT.  Modify
_APS_NEXT_CONTROL_VALUE to account for addition of IDC_CHOOSE_INST_TEXT.
* res.rc (IDD_CHOOSE): Modify choose dialog to use new field
IDC_CHOOSE_INST_TEXT for screen text.  Modify choose Dialog to allow hot keys
to select Prev, Curr, Exp.
* ini.h: Add new actions for ACTION_REDO and ACTION_SRC_ONLY.  Modify define
for LOOP_PACKAGES to include new actions ACTION_REDO and ACTION_SRC_ONLY.
* choose.cc: Add new Trusts for TRUST_REDO and TRUST_SRC_ONLY.
(paint): Modify to check TRUST_SRC_ONLY when determining Bitmap for source
Checkbox to use.
(build_labels): Add logic to allow for selection of Source only
Download/ReDownload/Install/Reinstall and also to Redownload/Reinstall current
version binary.
(dialog_proc): Add conditional display for file selection prompt based on
download vs install using IDC_CHOOSE_INST_TEXT.
(do_choose): Add new logic for TRUST_REDO and TRUST_SRC_ONLY selection and
modify logic for TRUST_UNINSTALL, TRUST_KEEP, and TRUST_NONE to handle the
instance where Source Download/Install was selected.  Modify log file to store
appropriate information regarding Action selected and the new actions that were
added (I.E.: ACTION_REDO and ACTION_SRC_ONLY).
* download.cc: Add include for <unistd.h> and "port.h".
(download_one): Modify parameter list to include the selected action for the
file to be downloaded.  Modify size check against expected size to include
check for ACTION_REDO and ACTION_SRC_ONLY.  Modify rename of .tmp file to also
remove the destination file if exists due to ability to redownload source and
binary now.
(do_download): Modify to also use ACTION_REDO and ACTION_SRC_ONLY in
calculation of Download Bytes.  Modify to also use ACTION_REDO and
ACTION_SRC_ONLY in determining files selected for download.
* install.cc (uninstall_one): Add check to treat a Reinstall like an upgrade so
current version will be uninstalled prior to reinstall.
(do_install): Add logic to handle ACTION_REDO and ACTION_SRC_ONLY for
uninstalling and installing binary and source packages.
* desktop.cc (make_passwd_group): Modify logic to account for a Source only
cygwin install when checking for cygwin to determine need for mkpasswd and
mkgroup.