feat(index.html):added download links (osx,ubuntu)

All assets are configured via shared.yaml and are located elsewhere in
the web. This could lead to broken assets at some point, but I am just
risking it for know, knowing that it's easily done to have local
resources.

Closes #106
[skip ci]

src/mako/index.html.mako

@@ -1,7 +1,7 @@
 <%
     import os
     import yaml
-    from util import (gen_crate_dir, api_index, crates_io_url)
+    from util import (gen_crate_dir, api_index, crates_io_url, program_name)
 
     title = 'Google Service Documentation for Rust'
 
@@ -70,9 +70,13 @@ DO NOT EDIT !
             <a class="mod" href="${api_index(DOC_ROOT, an, v, ad.make)}" title="${ad.make.id.upper()} docs for the ${an} ${v}">${ad.make.id.upper()}</a>
             % if api_name == 'api':
             <a href="${crates_io_url(an, v)}"><img src="${html_index.asset_urls.crates_img}" title="This API on crates.io" height="16" width="16"/></a>
+            % else:
+            % for os_name in ('ubuntu', 'osx'):
+            <a href="${html_index.download_base_url + '/google.rs/%s/%s/%s/%s' % (api_name, ad.cargo.build_version, os_name, program_name(an, v))}"><img src="${html_index.asset_urls.get('%s_img' % os_name)}" title="Download the 64bit program" height="16" width="16"/></a>
+            % endfor ## each os
             % endif
             % if not loop.last:
-, 
+,           
             % endif
         % endfor # each program type
         )</span><br/>

src/mako/lib/util.mako

@@ -49,5 +49,5 @@ ${canonicalName}\
 </%def>
 
 <%def name="program_name()" buffered="True">\
-${self.library_name().replace('_', '-')}\
+${util.program_name(name, version)}\
 </%def>

src/mako/lib/util.py

@@ -835,6 +835,9 @@ def gen_crate_dir(name, version, ti):
 def crates_io_url(name, version):
     return "https://crates.io/crates/%s" % library_to_crate_name(library_name(name, version))
 
+def program_name(name, version):
+    return library_name(name, version).replace('_', '-')
+
 def api_index(DOC_ROOT, name, version, ti, check_exists=True):
     crate_dir = gen_crate_dir(name, version, ti)
     if ti.documentation_engine == 'rustdoc':