Hook test run to setup.py

The tests can now be run bay calling `python setup.py test`.
Adds a list of required package

It seems that it only uses ScipY to get the light speed  constant.
Add a hook to Travis CI
Fix name of travis setup file.
Remove deprecated argument.

The argument `--use-mirrors` of `pip` have been deprecated.
Update required version of SciPy
Update version of Matplotlib and Astropy
Merge branch 'hotfix-synplot-abund' into development
Merge branch 'hotfix-periodic-table' into development

Creates a folder to store extra resources. The first one is the periodic
table.
Adds a faster function to load spectrum

It is 3 times faster than numpy.loadtxt.

I obtained from http://cyrille.rossant.net/numpy-performance-tricks/
Apply faster loading of spectrum

I also initialize this variable in the __init__
Merge branch 'development' into feature-fitting

Obtain the new function `loadtxtx_fast`.
Fix strip of string

The spectrum generated by Synspec has leading white spaces. The
`loadtxt_fast` function was not catching this.
Fix test of variable

I had initialize the `spectrum`function in the __init__, thus, I had to
change how to check its existence.
Start writing test fro Synplot
Merge branch 'development' into feature-fitting

Obtain fix to 'loadtxt_fast' function and Synplot tests.