Minor user profile submission counters text update

Changed the text in the submission counter so that instead of mentioning
"link type submissions" or "message type submissions" it calls them
"shared links" and "discussions started" for the text to be more like
the "Start a discussion" and "Share a link" buttons.

[BEFORE](http://i.imgur.com/K1zWA8L.png) |
[AFTER](http://i.imgur.com/vRhKHkE.png)
Minor user profile tabs description update

Removed the "To see X, click the X tab" bit from the user profile tabs
description. Mostly to cleanup the page description and also because the
header is where navigation is actually done and if a user doesn't read
the button that says "Comments" or "Submissions", they probably won't
read the description either. Also, if they managed to get to the user
profile, they probably have figured out how to navigate in WhoaVerse.
Additionaly, there's the "To see comments, click the comments tab." in
the overview page, whilst there is nothing mentioning the submissions
tab and IIRC that is there from when the overview tab only showed the
user's submissions (which back then was a bit confusing for those who
were used to reddit overview, since there was also a submitted tab with
the exact same functionality), but since then the overview tab is an
actual user overview, making each tab's button pretty self-explanatory
Another minor user profile tabs description update

Removed the "(most recent 200 submissions/comments)" because since
https://github.com/whoaverse/whoaverse/issues/174 was fixed, all
submissions and comments are displayed and not just the most recent 200.
Ridiculously minor button text update

Changed the "Submitted" button in the user profile header navigation to
"Submissions", since the submission history tab has submissions written
in the title and the url and not "submitted". Also, if it were to be
Submitted, shouldn't the comments button say Commented?

Side note: I shouldn't be commiting so fast, I keep missing something
and have to do another minor commit. :P
Merge pull request #178 from DanielFlamino/master

A few minor user profile text updates