Remove clojure-ini, use iniconfig

- clojure-ini doesn't seem to work at all:
  https://github.com/jonase/clojure-ini/issues/2

  Trying to run "lein test" failed too :(

- com.brainbot/iniconfig is working for me.
Fix the types of config vars that are numbers or lists.
Use .bindRoot

- alter-var-root wasn't working for me.  .bindRoot seems to be the
  escape hatch for the situation I've got.
The use of iniconfig means that all keys are strings.

- Get from *config* using string keys instead of symbols.
Merge pull request #6 from pcn/fix-config-updating

Fix config updating