Preliminary option handling revamp. Throughout, change load/save methods to

Preliminary option handling revamp.  Throughout, change load/save methods to
constructors/destructors which use new UserSettings methods.  Do not inherit
from UserSetting class.
* KeysSetting.cc (ExtraKeysSetting *ExtraKeysSetting::global): Define.
(ExtraKeysSetting::ExtraKeysSetting): Initialize some class members use new
UserSettings methods.
(ExtraKeysSetting::~ExtraKeysSetting): Use new UserSettings method.
* Makefile.am (setup_SOURCES): Eliminate UserSetting.h and UserSetting.cc.
* UserSettings.cc: Complete rewrite.  Implements new UserSettings class
methods.
* UserSettings.h: Complete rewrite.  Defines new UserSettings class methods.
* crypto.cc (ExtraKeys): Delete.
(add_key_from_sexpr): Use ExtraKeysSetting::instance rather than ExtraKeys.
(verify_ini_file_sig): Ditto.
* io_stream.h (io_stream): Define virtual << operators.
* localdir.cc (localDir): Delete.
* main.cc: Include headers which declar new dynamically invoked classes.
(main_display): New function.  Controls order of option setting and property
page setup.  Add new class invocations to force option setting initializtion.
(main): Invoke new UserSettings class constructor to populate new settings
class.  Call main_display() to do most of the setup work.  Call Settings.save
() to save all settings.
* net.cc (theSetting): Delete.
* site.cc (SiteSetting::save): Record whether we've saved the information
already.
(get_site_list): Just use value returned from new UserSettings method rather
than parsing a file.
(SiteSetting::getSavedSites): Ditto.
(write_cache_list): Use UserSettings operator to store mirror cache.
(save_cache_file): Ditto.
* source.cc (theSetting): Delete.
* win32.h: gcc-4 accommodation.