create param persister class
move writer into parent class
rename parent class
rewrite reader
create display_param helper
create to_h method
create #exist? method
rename views
do not specify layout
create Params#all
refactor param writer
create ParamAccessor class
rename #permalink to #to_url
move PARAM_DIR constant
refactor ParamFile class
update #all method
fix filemode attr_reader
make more methods private
fix entry sorting
move files into lib/params