added cl_particles_blood_size_min, cl_particles_blood_size_max, and cl_particles_bloo...

added cl_particles_blood_size_min, cl_particles_blood_size_max, and cl_particles_blood_alpha cvars
changed trails back to quake-style (spawn over distance, not over time)
pt_fade now takes a fade rate (in p->time2)
many tweaks to particle effets
loading screens work correctly now
cleaned up backend code a bit, now does not freak out if a texture upload occurs during rendering
added r_quickmodels (default: on) which makes single-pass models (the vast majority of models) store vertex data directly into the backend arrays (using R_Mesh_Draw_GetBuffer)
model vertex transforms are now applied *after* lighting, this avoids transforming the normals, and prepares for someday adding transforms to the backend
fixed view blend in gl_rmain.c to work correctly with fov values above 90
moved image resampling and mipmapping from gl_textures.c to image.c
now updates screen twice while connecting to a server (so it displays the 'trying...' messages)
improved directional shading of explosions
disabled r_lightmodelhardness since the default was nearly 1.0 anyway, 1.0 is a special quick case
R_LightModel now tints the model and can accept vertices/normals in either model or world coordinates (previously required world coordinates)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@1631 d7cf8633-e32d-0410-b094-e92efae38249