refactor: cfgFindRoot()

cfgFindRoot made clearer
errata: Readme.md
db classes introduced and split to files

+some refactor done
project folder/name detection changed

that fixes writing todo's in new blank files
let .todo go git itself
mysql support added

+ pyMySql included
+ early steps to make buffered task saving
Sql table definition finalized (so far)
unicode supported
dbFile accepts unicode
py files being utf-8; stupid cfg read error fix
.todo is created as project's opened if none

+ TodoDb moved to own file
clear out .todo