README.md: Adjust headings

I originally made these effectively <h2> headers because I didn't
want to compete with the GitHub headings when the file was viewed
on their web interface. As it turns out, GitHub renders this in an
HTML5 article tag, which sits in its own world on the page, so it
shouldn't matter.

Signed-off-by: Alan Orth <alan.orth@gmail.com>

README.md

@@ -1,12 +1,12 @@
-## Curriculum Vitae for Alan Orth
+# Curriculum Vitae for Alan Orth
 A CV written in LaTeX using the [moderncv](http://www.ctan.org/pkg/moderncv) class.
 
-### Sample
+## Sample
 Here's what it looks like with real data, using the "classic" style and blue color scheme:
 
 ![Image](/cv_sample.png?raw=true "Sample CV")
 
-### Why
+## Why
 I decided to start keeping my CV in LaTeX because:
 
 * I can never find my CV when I need it
@@ -14,7 +14,7 @@ I decided to start keeping my CV in LaTeX because:
 * LaTeX -> PDF ensures a consistent, beautiful layout
 * Writing your CV in a source-based language means you can track it in git (w00t!)
 
-### Usage
+## Usage
 To "build" a PDF you simply type:
 
     $ make
@@ -23,7 +23,7 @@ To clean up all generated and intermediate content, type:
 
     $ make clean
 
-### Pre-requistes for building
+## Pre-requistes for building
 Depending on your GNU/Linux distribution the package names may be different. Basically, you need the `texlive` package, as well as whichever "extras" package contains the moderncv stuff.
 
 __On Arch Linux:__