This patch adds a number of new features to pl_analyze:

* Support for rails logs
* Analyzing multiple logs at the same time
* List of most frequently encountered http codes
* Better command line handling
* Optional progress bar while parsing
* Optional ignoring of http:// URLs without domain
* Requests per second, time of first and last request logged
* Separate statistic for additional controllers
* Remove dependency on rails_analyzer_tools

Rails logs can only be parsed correctly if the entries are written one by one (lines not mixed up) as there is no way
to determine which rails process wrote wich line.

It also refactors the parser a bit, this was necessary to support the progress bar. It requires the 'progressbar' gem
to be installed.

Sorry for the large patch size. However, I thought these features might be useful to other people using pl_analyzer
as well.