Remove extra python version for Travis
Remove e-mail notification

It is too much e-mail.
Run Travis with miniconda

I copied some part from leouieda/fatiando travis.yml file.
Change command to run test

I could get it to install everything after getting some inspiration on
leouieda/fatiando travis.yml file. But then, the tests could not run. I
guess I had written the command in a bad way. I hope this fix it.

Related to #24.
Installs g77 to Travis

Travis was not compiling Synspec and Rotin because it lacked g77 and
ifort. I will try to install g77 on it.
Tries gfortran to install g77

Travis could not find the g77 package. I saw this way here:
https://groups.google.com/forum/#!topic/travis-ci/Yme-NTlcvUI
Comment lines to be able to use fort77

Up until now I could only complie this file using `g77` or the Intel
Fortran Compiler. By playing with `fort77`, it throwed an error on these
lines. I commented them and initial tests showed that there was no
difference on the final file. Synspec was still able to run.

These lines uses a fortran command called `SAVE`. I found this
explanation:

>  SAVE is a specification statement which can be used to ensure that
>  variables and arrays used within a procedure preserve their values
>  between successive calls to the procedure. Under normal circumstances
>  local items will become ``undefined" as soon as the procedure returns
>  control to the calling unit. It is often useful to store the values of
> certain items used on one call to avoid doing extra work on the next.

source: http://rsusu1.rnd.runnet.ru/develop/fortran/prof77/node156.html

Related to #24.
Compile Synspec and Rotin with fort77

Besides g77 and ifortran, it can now also compile them with fort77.

Related to #24.
Makes Travis install fort77

Instead of using gfortran or g77 as the fortran compiler, it now uses
fort77.
Uses nose to test

I found a way to use nose under Travis, thus I changed how it runs the
test scripts.
Remove requirements list

That is not needed anymore.
Adds astropy to Travis

Travis gave back an import error when running the tests.
Adds Astropy to the requirements list
Fix Travis setup file

I removed the command that install the package by mistake.
Change installation command for Travis

I do not have any extensions, so Travis can install S4 normally.
Comment test command for Travis.

I commented the test command because it will throw error.
The problem is not `nosetests` but it is that I need IDL to run some of the
tests. Then, I guess it will have to stay commented until I get rid of IDL.

Related to #24
Uncomment line for Travis

I commented the part that run the tests hoping that it would pass, but
instead returned me this error:

>Please override the script: key in your .travis.yml to run tests.
>The command "false" exited with 1.
>Done. Your build exited with 1.

By checking the website, I found that:

>In case script key is not provided in .travis.yml for Python projects,
> Python builder will print a message and fail the build.

I uncommented one line to test if it will pass.

Related to #24.
Run nosetests as a dry-run.

A real run will not work because there is no
IDL installed under Travis. Thus, to not run it, we added the --collect-only
argument. When the IDL dependcy is removed, take out this argument.
Add a Travis badge to README

This bagde is for the `travis` branch.
Fix typo