[fixed] Saved Views window rmb click problem

[Fonte Boa]

Micheus, i replaced wpc_sel_win.beam in C:\Program Files\wings3d_2.1.3\lib\wings-2.1.3\plugins\commands\
Therefore, multiple selections remain available in the window Saved Views.
And, as before, if i RMB click after select two or more views, a wings_crash.dump is generated.

---------------------------------

Dump written 2016-11-15_16-14
Version: 2.1.3
Window: <0.176.0>
Reason: {case_clause,2}

Short stack trace:
[]

Long stack trace:
[{wpc_views_win,get_selection,1,
[{file,"c:/Users/familjen/src/wings/plugins_src/commands/wpc_views_win.erl"},
{line,306}]},
{wpc_views_win,invoke_menu,1,
[{file,"c:/Users/familjen/src/wings/plugins_src/commands/wpc_views_win.erl"},
{line,338}]},
{wpc_views_win,handle_event,2,
[{file,"c:/Users/familjen/src/wings/plugins_src/commands/wpc_views_win.erl"},
{line,219}]},
{wx_object,handle_msg,5,[{file,"wx_object.erl"},{line,450}]},
{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]