build instructions style update

BUILD.md

@@ -4,22 +4,28 @@
 
 Start by getting a copy of the source code:
 
+```sh
 git clone https://github.com/micahflee/onionshare.git
 cd onionshare
+```
 
 *For .deb-based distros (like Debian, Ubuntu, Linux Mint):*
 
 Note that python-stem appears in Debian wheezy and newer (so by extension Tails 1.1 and newer), and it appears in Ubuntu 13.10 and newer. Older versions of Debian and Ubuntu aren't supported.
 
+```sh
 sudo apt-get install -y build-essential fakeroot python-all python-stdeb python-flask python-stem python-qt4
 ./build_deb.sh
 sudo dpkg -i deb_dist/onionshare_*.deb
+```
 
 *For .rpm-based distros (Red Hat, Fedora, CentOS):*
 
+```sh
 sudo yum install -y rpm-build python-flask python-stem pyqt4
 ./build_rpm.sh
 sudo yum install -y dist/onionshare-*.rpm
+```
 
 ## Mac OS X
 
@@ -27,6 +33,7 @@ To install the right dependencies, you need homebrew and pip installed on your M
 
 The first time you're setting up your dev environment:
 
+```sh
 git clone https://github.com/micahflee/onionshare.git
 cd onionshare
 echo export PYTHONPATH=\$PYTHONPATH:/usr/local/lib/python2.7/site-packages/ >> ~/.profile
@@ -38,14 +45,19 @@ The first time you're setting up your dev environment:
 pip install flask stem py2app
 # fixes a silly bug https://bitbucket.org/ronaldoussoren/py2app/issue/143/resulting-app-mistakenly-looks-for-pyside
 patch env/lib/python2.7/site-packages/py2app/util.py < setup/py2app.patch
+```
 
 Each time you start work:
 
+```sh
 . env/bin/activate
+```
 
 Build the .app:
 
+```sh
 python setup.py py2app
+```
 
 Now you should have `dist/OnionShare.app`.
 
@@ -70,8 +82,12 @@ To make an exe:
 
 OnionShare includes [nose](https://nose.readthedocs.org/en/latest/) unit tests. First,
 
+```sh
 sudo pip install nose
+```
 
 To run the tests:
 
+```sh
 nosetests test
+```