Add k_node_alloc() and k_node_free().
Removed swp files.
Removed test file.
Moved source files to klib.
Removed original klist files.
Add k_list_init().
Changed k_list_init() implementation and added k_list_free().
Added k_list_append().
Changed implementation of KList, removed sentinel.
Added k_list_prepend().
Added k_list_pop_head().
Added test about pop out a empty list.
added k_list_pop_tail().
Added k_list_remove().
Added k_list_remove_all().
Fixed bugs in k_list_remove() and k_list_remove_all().
Merge branch 'klist'

Author: kaizhang

Added basic implementation of double-link list.