Board/Thread Metadata: board thread count, etc

Added extra code to initialize the board and thread metadata rows on
import. Additionally, for boards.allCategories extra code has been added
to append the board metadata for each board found. While for threads,
the thread view count inc function has been tighten up and a new
function was created to increment the board's thread count and total
thread count upon import. This function will also recursively updated
the parent board's total thread count.