Make flash messages fixed and sticked to bottom

Improvements to English text

Fix the link to the project branches

Thanks!

Definitely sounds better like this.

Summary:

 - Mostly very small things involving use of "a", "the" etc.
 - "post-receive" hooks are usually written with the hyphen in the name .
 - I changed the Web Hooks page to have a title consistent with all the other
   pages in the settings area.
 - More consistent usage of full-stops in lists.

These are just a few very particular fixes for small grammatical issues,
intended to polish the reading experience.

I've reworded the first sentence to say "You don't have access to any projects",
which I think sounds more natural.

I've also used the "pluralize" ActionView helper for the user's projects_limit,
so that it still looks good when it says "You can create up to 1 project.".

Finally, I've tweaked the structure of the final sentence a little bit to make
it sound a bit better.

I've changed all the instances of "Nothing to show here" to specifically mention
the name of the entity of which there are none to show. This makes for a
slightly smoother reading experience.

Show permissions as a grid

Fix caching when using remote redis server

Update installation.md