fix cannot create directory or file on CentOS #253

Change method used to get combo entry text due to inexplicable
 GTK_IS_ENTRY (entry) failed

Test for non-null return string
update russian translation
case insensitive sort on Type, Owner columns
move debian/ to distros/debian/ and update README
Enter clicks Set, Esc twice clicks Unset in Set Key dialog
added manual GUI|Find-As-You-Type Search #258
BUILD DEBUG use -ggdb3
New File/Folder/Link enabled if no write access for As Root
fix cannot unset plugin key combo assignment
README links
move packages list to wiki
add kernel polling instructions to README
gtk2-compat.h fix gtk_combo_box_text_new_with_entry define gtk<2.24 #253
added configure option --with-gtk2 to force gtk2 only build
simplify build next README
mount curlftpfs in terminal for password entry #251

also update custom protocol handler script in manual to use run_in_terminal
socket command
mouse back/fwd buttons work anywhere in window
dont show empty (all items context hidden) custom submenus #215
path bar tab completion reworked, sorted
auto seek with invalid model