Display the Latex command for a keyword

What does your instant answer do?
	Looks for the key words (Latex, latex, tex) and return the latex command related to the keyword

What problem does your instant answer solve (Why is it better than organic links)?
	There are tons of latex commands and some are not exactly intuitive.  There's really no easy way
	to find a command other than digging around on cheat sheets.  This is a quick
	way to find the command an an example use of a few of the common latex math commands.  There are
	many more commands to add but this is a start. 
	
What are some example queries that trigger this instant answer?
	latex and 
	Latex integral
	tex summation

Which communities will this instant answer be especially useful for? (gamers, book lovers, etc)
	People writing latex documents and looking for math keywords.

Is this instant answer connected to an Ideas.DuckDuckHack or Duck.co thread?
	https://dukgo.com/ideas/idea/134/latex
	
Which existing instant answers will this one supercede/overlap with?
	none, I think.
	
Are you having any problems? Do you need our help with anything?
	I think the text format could look nicer.  Maybe move the usage to a new line?  

[x] Added metadata and attribution information
[x] Wrote test file and added to t/ directory
[x] Verified that instant answer adheres to design guidelines(https://github.com/duckduckgo/duckduckgo-documentation/blob/master/duckduckhack/styleguides/design_styleguide.md)
[] Tested cross-browser compatability

    Please let us know which browsers/devices you've tested on:
    - Linux 
        [] Google Chrome   
        [x] Firefox         
        [] Opera           
        [] IE 10