After the first API request, the database was locked as long as the API
server is running. This prevents a user to also use the command-line
client. This commit adds a new flag `-no-lock` that will close the
database after each API request.
Closes#234
Unlocking the different elements in cache flusher was deferred to the
end of the function. Unfortunately, being a for loop wrapped in a
goroutine, deferred were never executed.
Andrey Smirnov
Vincent Bernat
Sylvain Baubeau