README: fix title levels

Author: Artoria2e5

README.md

@@ -1,4 +1,4 @@
-# This is my version of brkirch's afsctool
+# RJVB's fork of of brkirch's afsctool
 
 > AFSC (Apple File System Compression) tool is a utility that can be used
 to apply HFS+ compression to file(s), decompress HFS+ compressed file(s), or
@@ -15,7 +15,6 @@ I have made several modifications, mostly concerning the compression feature:
   temporarily. No error checking is done for this feature; failure will lead to
   errors that are already caught.
 
-
 The main new feature that justifies the version bump, however, is the parallel
 processing feature, allowing the user to specify an arbitray (though positive :))
 number of threads that will compress the specified files in parallel.
@@ -27,6 +26,7 @@ This feature has two modes that each perform best in specific conditions:
   state disks, file collections that reside on different disks or collections with
   files of different sizes (including notably very large files). This mode is
   selected with the -J option.
+
 The performance difference is never enormous in my testing, but YMMV.
 
 Interestingly, the optimum performance (on large collections) is not necessarily
@@ -59,21 +59,20 @@ mode adopts the approach also used for LZVN compression, where the memory buffer
 as needed and thus only gets as large as needed (typically 4-5x smaller than in the singleshot
 mode). Singleshot mode might be marginally faster when enough RAM is available.
 
-
-### Installation
+# Installation
 
 afsctool depends on zlib (v1.2.8 or newer) and Google's sparsehash library and on CMake
 and pkgconfig for building. The OS zlib copy may be recent enough (it is on 10.12 and later) but to be
 certain to obtain the latest versions of both, use a package manager like MacPorts, Fink
 or HomeBrew. Be sure to follow the general installation and usage instructions for those
 projects, in particular how to update your PATH.
 
-# using MacPorts:
+## Using MacPorts:
 ```shell
 port install sparsehash zlib cmake pkgconfig
 ```
 
-# using HomeBrew:
+## Using HomeBrew:
 ```shell
 brew install google-sparsehash zlib cmake pkgconfig
 PKG_CONFIG_PATH=/usr/local/opt/zlib/lib/pkgconfig