Use InternedStrings for buffer contents
InternedStrings know their slots
scrolloff is now a line,column pair

Fixes #152
Use ',' instead of '|' as tuple option fields separators
Fix cpp indentation align to opening paren
Fix ragel.kak highlighting
update README
WordDB: Use interned strings pointing directly into the buffer line data
Add a coding style document

Fixes #58
Small refactor