Preliminary support for parsing Drupal 7.x source files. There is already a hook_perm() change in Drupal 7 which does not have handler code yet, but things which work the same way in Drupal 6 should work still.

Plus port an is_dir() change which was missing from this branch.

#219007 report and patch by hass: small installer files were merged into general.po, creating duplicate strings; they should not be merged (only applicable to 5.x versions of potx)

#205100 by phirdina: plural translations were missing in exported po files due to bugos database logic

 - backported some code style fixes from 6.1
 - backported relevant README changes from 6.x
 - removed hook_node_types() support, as it is a Drual 4.6 construct, not supported anymore
 - ported region name and default user role detection from 6.1
 - ported back hook_perm() error detection from 6.2
 - ported duplication marking for installer strings in runtime export from 6.1
 - better code when no file version was indentifiable, so the file name is included at least

#201253 report by Gocho, fix by myself: source strings already had quotes escaped, which is bad for translation lookups

Long month name bug discovered while doing Drupal 6 RC1 templates (forgot to commit to this branch as well 8 days ago)

#186798 by myself: _locale_export_string() was known as _locale_export_print() in Drupal 5, fix lazy backport

 - there could be a single but not English language
 - the n/a default value was not properly set
 - when the checbox is not set for translations, the file extension was missing

 - back with the translation exports, but initially just choosing the template language
 - fill in template header with language dependent values if language is choosen
 - option to include translations in the export now with proper plural support

Fix file name generation regex shortcoming identified why checking ubercart issues listed at #177763

#155106 and #155108 patches by myself: blacklist potx.inc, although this makes generating templates for potx itself a manual-only process, but other modules will have their templates generated without the potx.inc cruft. Also fixing the issue when we have no strings collected for a specific area (runtime or installer strings).

#149280 by myself: whitelist 'name', 'description' and 'package' keys from .info files as other values are cropping up, which we don't need for translation, so a blacklist approach was not feasible; thanks for Alexander Hass who reported the issue.

 - do not pass tokens, token lookup, and gathered strings around, it pollutes the argument lists and is a memory hog
   use global variables instead, which look less nice, but better for performance
 - allow potx to be used as an extraction API, by providing custom callbacks to store file versions,
   strings found, and even if building the basic POT files, a callback for the header generated
 - add drupal_set_message() functionality for web interface, allow marker error to be translateable
 - fix info file folding issues previously reported by Alexander Hass

Tested the changes both with the web interface and with the command line interface. Diffed the results against the Drupal core translation templates in CVS, and all seem to be right. The web interface even has the info folding bug fixed.