Move IpCounter to date-based tmpdir storage with daily cleanup

IpCounter files were stored in the cache directory without cleanup,
causing inode exhaustion on busy sites. Files are now stored in
tmp

Move IpCounter to date-based tmpdir storage with daily cleanup

IpCounter files were stored in the cache directory without cleanup,
causing inode exhaustion on busy sites. Files are now stored in
tmpdir/captcha/ip/Y-m-d/ with automatic daily cleanup via indexer.

Also reorganizes FileCookie to tmpdir/captcha/cookie/Y-m-d/ for
consistency and moves timeout config loading into IpCounter constructor.

fixes #146

show more ...

adjust tests and fix file cookie handling

first go at cleaning up the code

update tests