docs: update changelog

changelog.txt

@@ -1,10 +1,19 @@
-2019-02-18 ericw-tools 0.18.2
+2019-03-25 ericw-tools 0.18.2-rc1
+
+Bug fixes:
 
 - qbsp: fix "_mirrorinside" on bmodels
+- qbsp: fix t-junctions on bmodels (fixes sparkles, lightmap seams, phong shading)
 - qbsp: fix a case where func_detail faces were incorrectly deleted during outside-filling
+- light: fix seams on "_mirrorinside" geometry (#236)
+- light: fix black faces with sunlight pointing straight down
+- vis: fix for microleafs blocking vis (e.g. 0.01 units thick). 
+       This fixes HOMs appearing when a map was vised. (#261)
+
+Features:
+
 - qbsp: support a hybrid Valve 220 texturing + q2/q3 surface flags .map format
-- qbsp: added options for large (greater than +/-64000 units):
-- qbsp: -worldextent and -midsplitsurffraction options for large maps
+- qbsp: added -worldextent option for large maps (deault=65536, meaning +/-65536 units):
 - light: Add "_bounce" "-1" model entity key to prevent light from bouncing off those brushes
 - light: experimental support for lighting Quake 2 .bsp's