Code Cleanup: rename vars for detecting change to be more consistent

rename change/is_change/is_changed/modified -> changed
also use bools over int/short/char and once accidental float.
Fix T37617: "Add plane" was adding a 2*2 grid

Was a regression from rBaa3c06b41ca9, hope this time all things are OK again (note the X/Y subdivision values still are different than before (-1 for same result), but imho they make more sense this way).
Correct fix for T37617, (own recent regression)
Code cleanup: As Sergey stated on bf-committers one should use id_us_min() if the user counter has to be decremented and not decrement the counter by hand.
i18n module cleanup: remove hack used during svn -> git transition phase!
Fix T37225: UV map for closed curves incorrectly generated

Summary:
Curve ORCO was not calculating properly for cyclic 2D curves.

- Needed to split vertices for blender internal renderer.
  Otherwise it's not possible to map last face to a proper
  texture location.

- Needed to tweak curve->mesh conversion to respect cyclic
  flag along U direction.

- Removed check for orcodm in curve.c:add_orco_dm since
  this code is only called if there're enabled constructive
  modifiers on the curve.

Reviewers: brecht

Maniphest Tasks: T37225

Differential Revision: http://developer.blender.org/D45
Usual ui messages fixes...
User Interface: don't show macro args in tooltips

was often making much too big strings to show in a tip.
Fix 37571: Knife Select should be disabled when no faces are selected

also check a similar case for bisect
fix for error in own recent commit, removing orientations.
Sculpt Dynamic Topology: support collapsing edges without subdividing edges as well

This allows you to choose between subdivide edges, collapse and both. Being able to
only collapse edges can be useful to simplify meshes with accidentally introducing
more detail.

Reviewed By: psy-fi, carter2422

Differential Revision: http://developer.blender.org/D15
View3D: disable auto-perspective when orbiting the view out of a camera.
Code cleanup: Typo fix for image function, patch by kgeogeo.

Differential Revision: http://developer.blender.org/D46
Fix T37471: Copy/Paste objects broke relative paths
Fix: Text editor, blank lines were being indented

Summary: fixes T37613

Reviewers: campbellbarton, sergey

Reviewed By: sergey

Maniphest Tasks: T37613

Differential Revision: http://developer.blender.org/D42
Blender Internal: Fix material preview that the bounce lights permanently disappear once volume material is used.
Fix T37624: Rename Marker does not update Marker in 3D View until Frame Change

Was simply missing notifier listener in 3D viewport.

Also fixes missing refresh when adding a marker.
Fix own regression in rB254aa8f3a0fb: Titles and sub-titles in menus were drawn shifted to the right.

Reported by plasmasolution over IRC, thanks.

Also fixes wrong handling of "sub-titles" with icons in EnumO menus (they were just treated as text-only ones).

Dev notes: in fact, that clean up commit revealed kind of an "hidden bug that happend to work well"
(or at least, a very bad hack): with titles without icon, code used to use uiItemL with ICON_NONE.
However, as the root layout is a menu one, internal ui code would add a dummy blank icon,
and set UI_HAS_ICON flag for the label button. But in the affected menus, code afterward assigned
UI_TEXT_LEFT to but->flag, thus erasing the (internal) UI_HAS_ICON. As UI_TEXT_LEFT was moved to
but->drawflag, the internal flag was no more erased, and the fake icon was drawn, creating that
shift-to-the-right effect. Turns out we do not even have to set UI_TEXT_LEFT in these cases,
just add label buttons without icon is enough!
Math library: minor additions sqrtf_signed and copy_v2_fl2
Screw Modifier: copy face data when the original face is known.

also de-duplicate code for handling the closing face strip.