Issue #269877 by neochief, roderik, akaliel, mathieu, jct, Jo Wouters, fago, ufku, fmjrey, nonsie, pfournier: avoid duplicate paths (again) in path_set_alias()

Issue #1260932 by DjebbZ, pwolanin: hook_nodeapi() optional arguments should not be made required by some core modules either

- Patch #335385 by Dave Reid: fixed maxlength of path alias fields to be consistent with the database.

#216404 by Rob Loach: path_nodeapi() only worked for users with permissions, although node loading requires the path to be loaded

#200069 by keith.smith: new standard for 'more information' links in module help texts, as the handbook we referred to before was renamed

#197297 by DanW (as GHOP 17), and keith.smith: clean up lots of help texts, update to drag and drop functionality, drupal.module removal, etc

 - whitespaces at end of lines
 - indentation
 - control structure usage
 - whitespace in empty lines
 - phpdoc comment formatting

#154517 by chx and Desbeers: usability fixes for path module (required fields, permission info and resetting the filter made possible), and fixing language usage on nodeapi update in path_nodeapi

#156910 by asimmonds: fix code indentation problems introduced with new code in this development cycle; only whitespace changes

  unanimously agreed to rollback the deletion API.  We all support the
  features this patch added, yet not its actual design and implementation.
  After some talk, we decided that it would be better for Drupal -- in the
  long term -- not to go with a solution that isn't 100%. We also recognize
  that in the short term, this patch would have been useful addition. So
  let's figure out how we can implement this properly in D7.

#154064 by pwolanin: get hook_help() up to speed to menu changes, allowing router path based lookups, and also full path argument lookup with a passed argument array

- Patch #146910 by dww: only allow enabling modules with the same Drupal core compatibility version.