Shader code cleanup

See merge request !1103

I am going to die :D (closes #337)

Closes #337

See merge request !1183

Fix clients being able to skip credits AGAIN (closes #339)

Closes #339

See merge request !1182

A special stage is a special stage, even outside of coop.

Closes #211

See merge request !1180

Don't count demo playback as visiting a level.

Closes #327 and #340

See merge request !1177

Add `-splitscreen` commandline parameter

See merge request !1175

Add P_CeilingzAtPos function

See merge request !1164

serverrunning means that you are actually the server.

Replace cvar initializers with a macro

See merge request !1178

Provide a default exe manifest

See merge request !1174

Fix some theoretical crashes when using the P_*XYMovement, P_*ZMovement, and P_RailThinker functions in Lua.

See merge request !1173

Add error message when the GDI Generic OpenGL renderer is encountered in Windows

See merge request !1172

Expose MODVERSION to Lua (because for some reason it wasn't).

See merge request !1158

Updated 16 bit momentum values to 32 bit in demos, changed demo version

See merge request !1157

Support sectors as sound origins in Lua

See merge request !1144

Autocomplete aliases in console

See merge request !1113

Expose V_GetStringColormap to Lua via v.getStringColormap().

See merge request !1111

Chain Homing with Attraction Shield

See merge request !1109

PlayerCmd Port

See merge request !1072

Fix some theoretical crashes when using the P_*XYMovement, P_*ZMovement, and P_RailThinker functions.

2.2.8 prep

See merge request !1170

Fix uninitialized variable issue in patches with missing grAb chunks

See merge request !1171

Prevent Canarivore gas from teleporting up walls

See merge request !1154

Fix #178

Closes #178

See merge request !1112

Remove "The OpenGL renderer is incomplete" notice (closes #281)

Closes #281

See merge request !1169

Fix graphics replacements not taking effect via -file

See merge request !1168