Skip "dot" files in layout

As a vim user, .filename.swp files pop up.  This change prevents hugo
from reading those files.
Removing GetSection

Using GetXXX is not idiomatic to Go.  Also added a bunch of unit testing
around this method.
Fix benchmark so the buffer is read each time.

The bytes.Buffer was exhausted after the first read.  Creating a new
reader each invocation catpures the correctly timing.
Update .gitignore to ignore *.swo files

For the fellow vim user.
Test cases for ignoreDotFile

Meant to commit this earlier, but it's a basic unit test.
RenderThing test cases

Provide unit test support RenderThing.

One observation is that creating the site.Tmpl variable is a one time
event.  site.Tmpl doesn't like additional templates with the same name.
This means that updating a template while in --watch mode requires
throwing away the entire Site object and creating a new one.  Not that
this is a bad idea, but it is something I discovered while working on
these unit tests.
Add 404.html for gh-pages

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>
Wordpress summaries

Allow full control of summaries which can be rendered as html rather
than text.  Using a `<!--more-->` html comment in your markdown / rst
you can indiciate where the summary should end and have the summary
converted to html.

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>

Conflicts:
	hugolib/page_test.go
Return any error reported by RenderHomePage

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>
Refactored added RenderThingOrDefault and tests

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>

Conflicts:
	hugolib/site.go