combined python2.7 and 3.4 into one Dockerfile since it's just for testing anyway

Dockerfile.py27

@@ -1,13 +0,0 @@
-FROM ubuntu
-MAINTAINER Jim Rybarski <jim@rybarski.com>
-
-RUN mkdir -p /var/nds2
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    python-numpy
-
-COPY . /opt/nd2reader
-WORKDIR /opt/nd2reader
-RUN python setup.py install
-WORKDIR /var/nd2s
-
-CMD /usr/bin/python2.7

Makefile

@@ -3,5 +3,8 @@
 build:
 	docker build -t jimrybarski/nd2reader .
 
-shell:
-	docker run --rm -v ~/Documents/nd2s:/var/nd2s -it jimrybarski/nd2reader
+py2shell:
+	docker run --rm -v ~/Documents/nd2s:/var/nd2s -it jimrybarski/nd2reader python2.7
+
+py3shell:
+	docker run --rm -v ~/Documents/nd2s:/var/nd2s -it jimrybarski/nd2reader python3.4