Update changelog and migration guide

CHANGELOG.md

@@ -1,8 +1,9 @@
-4.5.0 / WIP
+5.0.0 / 2015-09-30
 ------------------
 
-- Keep tabs (don't replace with spaces)
+- Keep tabs (don't replace with spaces).
 - Don't wrap iframes with paragraphs (according to spec update).
+- Changed emphasis algorithm to match one described in CM spec.
 
 
 4.4.0 / 2015-07-18

docs/5.0_migration.md

@@ -15,4 +15,6 @@ External API did not change.
 - added `stateBlock.sCount` to calculate indents instead of `stateBlock.tShift`, it only differs if tabs are present:
   - `stateBlock.tShift` is used to calculate a number of *characters* (tab is 1 character)
   - `stateBlock.sCount` is used to calculate the block *offset* (tab is 1-4 characters depending on position)
-
+- added `stateInline.ruler2` and `stateInline.delimiters` needed to parse emphasis-like markup better
+  - emphasis-like tags now can't be skipped with `stateInline.skipToken`, they treat a sequence of markers (e.g. `***`) as a token instead
+  - `stateInline.delimiters` is linked with `stateInline.tokens`, so truncating/splicing `stateInline.tokens` may break things