use to_be_current_line matcher
allow newline to be included before and after the block
add test for linewise objects and fix pasting problem
delete surrounds in each line of a blockwise object
rename a variable
add test for a blockwise object
fix a problem when cursor overruns
add test for uneven blockwise objects
filetype specific settings have higher priority than '-'
add test for filetype specific settings
fix a tiny mistake
implement an operator to replace blocks

but note that this implementation has a bug for undo list
disable autoindent
improve a test message
fix a bug when the object is at the end of file
throw an exception when the untreatable corner case happens
add test for <Plug>(operator-surround-replace)