Updated Background (markdown)

Background.md

@@ -1,14 +1,14 @@
-### History
+# History
 jemalloc started out as the memory allocator for a programming language runtime Jason Evans was developing in 2005, but language design changes made the allocator superfluous. At the time, [FreeBSD](http://www.freebsd.org/) was in need of an SMP-scalable allocator, so he integrated jemalloc into FreeBSD's libc, and then made a long series of improvements to scalability and fragmentation behavior.
 
 In late 2007, the [Mozilla Project](http://www.mozilla.org/) was hard at work improving [Firefox's](http://www.mozilla.com/firefox/) memory usage for the 3.0 release, and jemalloc was used to solve fragmentation problems for Firefox on [Microsoft Windows](http://www.microsoft.com/windows/) platforms. You can read [here](http://blog.pavlov.net/2008/03/11/firefox-3-memory-usage/) about the fruits of that labor. Many general jemalloc enhancements resulted from Firefox-related efforts. More recently, in 2010 Mozilla sponsored integration of [Apple Mac OS X](http://www.apple.com/macosx/) support into the stand-alone jemalloc, and in 2012 contributed [MinGW](http://www.mingw.org/) Windows support.
 
 Starting in 2009, Jason Evans adapted jemalloc to handle the extreme loads [Facebook](http://www.facebook.com/) servers commonly operate under, and added numerous features that support development and monitoring. Facebook uses jemalloc in many components that are integral to serving its website. Facebook supports numerous open source projects, and is to thank for sponsoring many jemalloc features.
 
-### Intended use
+# Intended use
 XXX
 
-### Adoption
+# Adoption
 Major uses of jemalloc include:
 * [FreeBSD](http://www.freebsd.org/)
 * [NetBSD](http://www.netbsd.org/)
@@ -21,7 +21,7 @@ Major uses of jemalloc include:
 * [Aerospike](http://www.aerospike.com/)
 * [Android](https://github.com/android/platform_bionic)
 
-### Additional documentation
+# Additional documentation
 The following documentation is dated or otherwise unsuited to wiki form:
 * <a href="http://jemalloc.net/jemalloc.3.html">jemalloc(3) manual page</a>: The manual page for the latest release fully describes the API and options supported by jemalloc, and includes a brief summary of its internals.
 * <a href="http://www.facebook.com/notes/facebook-engineering/scalable-memory-allocation-using-jemalloc/480222803919">Facebook Engineering post</a>: This article was written in 2011 and corresponds to jemalloc 2.1.0.