Removed lots of unnecessary casts to float of the Math methods. Also removed some other minor implicit casts

Edit Selection Mode: rotating sectors with plane equation slopes now works correctly if the sectors are not rectangular

Edit Selection Mode: slopes of 3D floor control sectors are now properly updated when moving/rotating sectors (only when not pasting)

Fixed an issue in Edit Selection Mode that could cause Out Of Memory exceptions with vertices that are slightly off grid in the 32 bit version

Using Edit Selection Mode on sectors with plane equation slopes works correctly now (flipping still doesn't work)

Decoupled plane equation slopes from sector heights. This means that changing sector heights will not change those slopes (use the offset box in the "slope" tab of the Edit Sector Dialog instead)

Added option to lock texture offsets of 3D floors when dragging the tagged sectors

Significantly reduced video memory usage when pasting sectors. Should also significantly increase speed when pasting many sectors. Fixes #400.

Fixed a crash in Edit Selection Mode when visual sloping was previously used to make the slope of a sector perfectly planar

Moved smart grid transform into Linedefs Mode and Vertices Mode, so it also works when simply highlighting a linedef or vertex. When doing smart grid transform on a linedef it'll also use the vertex closest to the mouse cursor as the origin instead of always the start vertex

Fixed a crash that would happen when the line slope things (9500/9501) are used but the linedef they are tagged to doesn't have a front sidedef. Fixes #398.

Added option to select behavior (Tools -> Preferences -> Editing) of scaling when auto-aligning textures on floors/ceilings (use base scale of 1 (default), use current scale as base, never scale)

Aligning textures on the X axis now works correctly with negative scale values when world panning is not enabled.

Fixes for raisesectortonearest and lowersectortonearest action when used on slope handles to account for float rounding errors

The sloping between handles action is now a bit more convenient and tries to figure out what the user wants to do even if not exactly two slope handles are selected.

- Smart pivot handles are now shown for the highlighted slope handle

- Added action to slope selected floors/ceilings between selected slope handles (default key: Ctrl-F)
- Added Shift-W as default key to toggle visual slope picking

- If geometry is selected and the geometry the modified slope handle belongs to is not selected it will now also be modified
- Made the slope handles hover closer to the geometry

Improved drawing length of slope handles on sloped lines (still too short, possibly because of aspect ratio correction?)

The slope handle closes to the mouse cursor will now always be picked (no minimum distance required anymore)

Also fixed some cases where slopes were applied incorrectly