Update the Dockerfile for experimenting with NeoVim testing

Dockerfile

@@ -1,25 +1,18 @@
 FROM tweekmonster/vim-testbed:latest
 
-RUN install_vim -tag v8.0.0000 -build \
-                -tag v8.0.0027 -build
+RUN install_vim -tag v8.0.0027 -build \
+                -tag neovim:v0.1.7 -build
 
-# the clang package includes clang-tidy
 ENV PACKAGES="\
     bash \
     git \
     python \
     py-pip \
-    nodejs \
-    gcc \
-    g++ \
-    clang \
 "
 RUN apk --update add $PACKAGES && \
     rm -rf /var/cache/apk/* /tmp/* /var/tmp/*
 
 RUN pip install vim-vint==0.3.9
 
-RUN npm install -g eslint@3.7.1
-
 RUN git clone https://github.com/junegunn/vader.vim vader && \
     cd vader && git checkout c6243dd81c98350df4dec608fa972df98fa2a3af