Add support for format of "Keep a Changelog" (#11)

* Add support for format of "Keep a Changelog"

* Advertise support of "KeepAChangelog" to README.md

* Add support for Windows line endings

README.md

@@ -6,7 +6,7 @@
 
 You need:
 
-- a CHANGELOG with the following format:
+- a CHANGELOG following the format of [keep a changelog](http://keepachangelog.com/en/1.0.0/) or a CHANGELOG with the following format:
 ```md
 # X.Y.Z - ...
 

github-release-from-changelog.js

@@ -79,22 +79,27 @@ if (tagMatches === null) {
 // changelog
 var body = []
 var start
+const changelogLines = changelog.replace(/\r\n/g, "\n").split("\n")
+// determine whether the log format of http://keepachangelog.com/en/1.0.0/: check the first line and check if there is a second level heading linking to the version diff
+const isKeepAChangelogFormat = (changelogLines[0] === "# Changelog") && (changelog.indexOf("\n## [" + version + "]") !== -1)
+// console.log(isKeepAChangelogFormat);
+
 // read from # version to the next # .*
-changelog.split("\n").some(function(line, i) {
+changelogLines.some(function(line, i) {
   // start with the # version
-  if (!start && line.indexOf("# " + version) === 0) {
+  if (!start && ((line.indexOf("# " + version) === 0) || (isKeepAChangelogFormat && line.indexOf("## [") === 0))) {
     start = true
   }
   // end with another # version
-  else if (start && line.indexOf("# ") === 0) {
+  else if (start && (line.indexOf("# ") === 0 || (isKeepAChangelogFormat && line.indexOf("## [") === 0))) {
     return true
   }
   // between start & end, collect lines
   else if (start) {
     body.push(line)
   }
 })
-body = body.join("\n")
+body = body.join("\n").trim()
 
 // prepare release data
 var releaseOptions = {