Plus a few styling enhancements.

[[Split portion of a mixed commit.]]

- remove unused imports
- remove/comment unused vars
- fix for some bugs with unused vars being used

from Lawrence D'Oliveiro (ldo)

READ THIS TO AVOID A LOT OF WORK!

New way of linking to tracker pages: just use the parameter "aid" (artifact ID),
to avoid a lot of manual updates later in wiki and svn.

Example:
=========

OLD WAY TO LINK TO TRACKER
-----------------------------

Complete url of a script in Upload
http://projects.blender.org/tracker/index.php?func=detail&aid=25349&group_id=153&atid=467

If we move this in contrib this url will become
http://projects.blender.org/tracker/index.php?func=detail&aid=25349&group_id=153&atid=468
467 becomes 468, so we have to update this in wiki page.

Later on, when this moves into Trunk, the url will become
http://projects.blender.org/tracker/index.php?func=detail&aid=25349&group_id=153&atid=469
468 becomes 469, so we have to update the url in wiki page and svn.

Annoying!

NEW WAY TO LINK TO TRACKER
-----------------------------

Best way to link to tracker page is using:
http://projects.blender.org/tracker/index.php?func=detail&aid=25349

Use "func=detail"
Use "aid"            (which is the "artifact ID")

DON'T use "group_id" (which is the project ID, bf-extensions is project 153)
DON'T use "atid"     (which is the "artifacts tracker ID")

Like this, the url is unique, and we will avoid to update wiki pages and svn after moving pages
 


[[Split portion of a mixed commit.]]

- in wiki page urls: "File_I-O/"     -> "Import-Export/"
- in categories:     "Import/Export" -> "Import-Export"
- 1 tab to 4 spaces
- some tuple formatting, just to be very picky :P

changed skelegon up-vector to bone roll conversion, should better match now
switch to Object mode before adding meshes/armatures, prevents new bones from being added into the currently edited armature

by Filiciss Muhgue (filiciss). Thanks a lot!

Part 2: Extensions

safely create new edges.
trailing whitespace cleanup.

- include bl_addon_info just under the gpl, faster parsing.
- use newstyle classes + __slots__ to disallow arbitrary attributes to be set.
- dont cycle ecitmode, instead use calc_edges argument to mesh update.
- use string formatting for print's.

[[Split portion of a mixed commit.]]