Update docs

doc/getstarted/build_and_install/build_from_source_en.md

@@ -101,8 +101,8 @@ As a simple example, consider the following:
     ```bash
     # necessary
     sudo apt-get update
-    sudo apt-get install -y g++ make cmake build-essential python python-pip libpython-dev git
-    sudo pip install wheel numpy
+    sudo apt-get install -y g++ make cmake build-essential python python-pip python-numpy libpython-dev git
+    sudo pip install wheel
     sudo pip install 'protobuf>=3.0.0'
     ```
   

paddle/scripts/docker/Dockerfile

@@ -9,13 +9,13 @@ RUN apt-get update && \
     apt-get install -y git python-pip python-dev openssh-server && \
     apt-get install -y wget unzip tar xz-utils bzip2 gzip coreutils && \
     apt-get install -y curl sed grep graphviz libjpeg-dev zlib1g-dev && \
-    apt-get install -y python-matplotlib g++ && \
+    apt-get install -y python-numpy python-matplotlib g++ && \
     apt-get clean -y
 
 RUN pip install --upgrade pip && \ 
     pip install 'protobuf==3.1.0.post1' && \
-    pip install -U numpy wheel pillow && \
-    pip install -U BeautifulSoup docopt PyYAML sphinx && \
+    pip install -U wheel pillow BeautifulSoup && \
+    pip install -U docopt PyYAML sphinx && \
     pip install -U sphinx_rtd_theme recommonmark jupyter
 
 RUN curl -sSL https://cmake.org/files/v3.4/cmake-3.4.1.tar.gz | tar -xz && \

paddle/scripts/docker/Dockerfile.gpu

@@ -9,13 +9,13 @@ RUN apt-get update && \
     apt-get install -y git python-pip python-dev openssh-server && \
     apt-get install -y wget unzip tar xz-utils bzip2 gzip coreutils && \
     apt-get install -y curl sed grep graphviz libjpeg-dev zlib1g-dev && \
-    apt-get install -y python-matplotlib g++ && \
+    apt-get install -y python-numpy python-matplotlib g++ && \
     apt-get clean -y
 
 RUN pip install --upgrade pip && \ 
     pip install 'protobuf==3.1.0.post1' && \
-    pip install -U numpy wheel pillow && \
-    pip install -U BeautifulSoup docopt PyYAML sphinx && \
+    pip install -U wheel pillow BeautifulSoup && \
+    pip install -U docopt PyYAML sphinx && \
     pip install -U sphinx_rtd_theme recommonmark jupyter
 
 RUN curl -sSL https://cmake.org/files/v3.4/cmake-3.4.1.tar.gz | tar -xz && \