Added ability to enable/disable controls in the UDMF map element editing dialogs based on UDMF fields specified in the game configurations (#953)

Visual Mode: the effect of slope things are now only applied if they are specified in the game configuration

Game Configurations: added support for enabling or disabling support for vertex heights in UDMF game configurations

Visual Mode: fixed a problem where flood selection did not work correctly when sidedefs were previously marked by other actions

UDMF type handler: fixed a problem where default values provided as integers for floating point fields failed to convert properly

Visual Mode: fixed a problem where flood selection would operate from all selected surfaces and not just the clicked on one. This behavior can be reverted by enabling the "Use buggy flood select in Visual Mode" option in Preferences -> Editing (#969)

Visual Mode: fixed a problem where flood selection would operate from all selected surfaces and not just the clicked on one. This behavior can be reverted by enabling the "Use buggy flood select in Visual Mode" option in Preferences -> Editing

Text file parser: fixed a problem where parsing could fail if the file ended with a comment without an trailing newline

Game Configurations: fixed a crash when no default values for UDMF integer or  floating point fields are set

Game Configurations: UDMF integer and floating point fields can now have default values other than 0

OBJ Exporter: fixed a problem where the wrong textures were used on 3D floors when they have the "use upper/lower texture" flag set

Game configurations: renamed lightmap things from static to lightmap. Added pulsing, flickering, and random flickering lightmap things

Visual Mode: fixed a problem where floors/ceilings could not be changed in size if the user tried to change their texture offset in a non-UDMF map

Game Configurations: fixed a problem where the enum list of enum bits handlers was not set for UDMF fields

Visual Mode: fixed a problem where sloped 3D floors with an alpha value of less than 128 were not shown at all instead of fully opaque. Fixes #954

Draw Curve Mode, Draw Ellipse Mode, Draw Rectangle Mode: added option to place things at the designated vertex positions instead of drawing geometry (#956)

Point Thing at Cursor: check for a thing's fixedrotation rather than its category's arrow setting (#957)

Visual Mode: when applying camera rotation and pitch to things a status message will now be displayed. Fixes #955

Visual Mode: fixed an issue where trying to apply a rotation to things that were not seen yet would cause a crash

Fixed a problem where not selected geometry and things could not be dragged when the "don't move selection if any part of it is outside of map boundary" option was enabled

3D Floor Mode: fixed an issue where new control sectors could not be created if any sector's bounding box completely encompassed the Control Sector Area

In Sound Propagation Mode you can set the start (default: Shift+S) and end (default: Shift+E) sectors between which a path the sound can travel will be found and displayed.

Visual Mode: fixed a problem where the selection order was not kept when synchronized selection between visual and classic modes was enabled. Fixes #938

Visual Mode: fixed a problem where things directly touching the top of 3D floors were rendered with the incorrect brightness. Fixes #940