Update installation docs

app/views/docs/installation.html.slim

@@ -4,13 +4,14 @@ markdown:
 
   # Installation
 
-  The latest stable version of asciinema recorder can always be installed or
-  updated to via [pip](http://www.pip-installer.org/en/latest/index.html)
-  (prefered) or easy\_install:
+  The latest stable version of asciinema recorder can always be found at
+  [pypi.python.org/pypi/asciinema](https://pypi.python.org/pypi/asciinema).
+  You can install or update it via
+  [pip](http://www.pip-installer.org/en/latest/index.html):
 
       sudo pip install --upgrade asciinema
 
-  Alternatively:
+  Alternatively, if you don't have `pip`, you can use `easy_install`:
 
       sudo easy_install asciinema
 
@@ -30,3 +31,8 @@ markdown:
   [AUR](https://aur.archlinux.org/packages/asciinema/) package:
 
       yaourt -S asciinema
+
+  ## No native package for your operating system?
+
+  If you use some other operating system and you know how to build a native
+  package for it then don't hesitate, build one and let us know.