Fix whitespace and update examples and organization

php/content.md

@@ -66,34 +66,56 @@ Where `src/` is the directory containing all your php code and `config/` contain
 
 ### How to install more PHP extensions
 
-We provide two convenient scripts named `docker-php-ext-configure` and `docker-php-ext-install`, you can use them to easily install PHP extension.
+We provide the helper scripts `docker-php-ext-configure`, `docker-php-ext-install`, and `docker-php-ext-enable` to more easily install PHP extensions.
+
+#### PHP Core Extensions
 
 For example, if you want to have a PHP-FPM image with `iconv`, `mcrypt` and `gd` extensions, you can inherit the base image that you like, and write your own `Dockerfile` like this:
 
 ```dockerfile
-FROM php:5.6-fpm
-# Install modules
+FROM php:5-fpm
 RUN apt-get update && apt-get install -y \
         libfreetype6-dev \
         libjpeg62-turbo-dev \
         libmcrypt-dev \
         libpng12-dev \
-    && docker-php-ext-install iconv mcrypt \
+    && docker-php-ext-install -j$(nproc) iconv mcrypt \
     && docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
-    && docker-php-ext-install gd
-CMD ["php-fpm"]
+    && docker-php-ext-install -j$(nproc) gd
 ```
 
 Remember, you must install dependencies for your extensions manually. If an extension needs custom `configure` arguments, you can use the `docker-php-ext-configure` script like this example.
 
-### How to install PECL extensions
-Some "extension" are in reality [PECL](https://pecl.php.net/) extension. To install a pecl extension you need to do this (for memcached) :
+#### PECL extensions
+
+Some extensions are not provided with the PHP source, but are instead available through [PECL](https://pecl.php.net/). To install a PECL extension, use `pecl install` to download and compile it, then use `docker-php-ext-enable` to enable it:
+
+```dockerfile
+FROM php:5-fpm
+RUN apt-get update && apt-get install -y libmemcached-dev \
+	&& pecl install memcached \
+	&& docker-php-ext-enable memcached
+```
+
+#### Other extensions
+
+Some extensions are not provided via either Core or PECL; these can be installed too, although the process is less automated:
 
 ```dockerfile
-FROM php:5.6-fpm
-# Install pecl extension
-RUN apt-get update && apt-get install -y libmemcached-dev && pecl install memcached
-CMD ["php-fpm"]
+FROM php:5-apache
+RUN curl -fsSL 'https://xcache.lighttpd.net/pub/Releases/3.2.0/xcache-3.2.0.tar.gz' -o xcache.tar.gz \
+    && mkdir -p xcache \
+    && tar -xf xcache.tar.gz -C xcache --strip-components=1 \
+    && rm xcache.tar.gz \
+    && ( \
+        cd xcache \
+        && phpize \
+        && ./configure --enable-xcache \
+        && make -j$(nproc) \
+        && make install \
+    ) \
+    && rm -r xcache \
+    && docker-php-ext-enable xcache
 ```
 
 ### Without a `Dockerfile`