Tests Fail on 0.5 & Cleanup

[lruthotto]

Currently, the tests for this package fail on julia 0.5.

Just looking through the package, here are some things that for sure need fixing:

• Changing the syntax of RemoteChannels
• change Base.ASCIIString to String
• update the testing files .travis.yml and appveyor.yml
• add badges for tests and coverage here to the Readme.md

While we're at it we might want to do some cleanup and other improvements. I think the following methods are not needed:

• everything in diagM.jl
• everything in sparseUtils.jl (see also same file in jInv.Utils)
• add docstrings