refactored unit test: test_protocol_search.rb
modified add_msg utility function
AssertUtility module
modified for protocol decoder test.
refactored unit test: test_protocol_decoder.rb
early assertion at DSL
refactored unit test: test_protocol_decoder.rb
new DSL keyword: assert.equal_lines
refactored unit test: test_protocol_decoder.rb
assert_imap_command utility function
refactored unit test: test_protocol_decoder.rb
mail store utility function
refactored unit test: test_protocol_decoder.rb
make_string_source utility function
refactored unit test: test_protocol_decoder.rb
reload_mail_store utility function
refactored unit test: test_protocol_decoder.rb
utf7 encode/decode utility function

constant variables for utf8 and utf7 mailbox name
imap/net for utf7 encode/decode
refactored unit test: test_protocol_decoder.rb
renamed test case method names

test_subscribe_not_implemented -> test_subscribe_dummy
test_unsubscribe_not_implemented -> test_unsubscribe_dummy
test_lsub_not_implemented -> test_lsub_dummy
test_lsub_utf7_mbox_name -> test_lsub_dummy_utf7_mbox_name
refactored unit test: test_protocol_decoder.rb
test_capability
refactored unit test: test_protocol_decoder.rb
test_logout
refactored unit test: test_protocol_decoder.rb
test_login
refactored unit test: test_protocol_decoder.rb
test_select
refactored unit test: test_protocol_decoder.rb
test_select_utf7_mbox_name
refactored unit test: test_protocol_decoder.rb
test_examine
refactored unit test: test_protocol_decoder.rb
test_examine_utf7_mbox_name
refactored unit test: test_protocol_decoder.rb
test_create
refactored unit test: test_protocol_decoder.rb
test_create_utf7_mbox_name
refactored unit test: test_protocol_decoder.rb
test_delete