Improved usability of Makefiles

Replaced mastermake with a makefile, which calls the lower level make
files.  This allows systems that cannot update their default compiler
to install davitpy without manually changing all of the lower level
model makefiles.

Lower level makefiles (iri, hwm, tsyganenko, and raydarn) and the
README were also updated to be compatible with this change.

Excess spaces were removed from MPIutils.f90 since I opened it to see
what it did.
Update README.md
Back FOV

Restored ability to plot and calculate azimuths for the rear
field-of-view that already exists in Go.
Revert "Back FOV"

This reverts commit a656d6c94cc5d0ffb65a1e4e03f53e01344e670c.
Update README.md

Updated README to reflect new process of not using mastermake
Delete Makefile

Upper level makefile is not needed for nstallation
Revert "Delete Makefile"

This reverts commit 40d4259a443602df57b011a89f7796fc46cd505d.
Delete mastermake

Deleted mastermake, which is no longer needed since setup.py handles the model compilations
Update README.md

Added instructions for only compiling models
Delete hwmupdatemod.mod

Removed, this file is created upon compilation
Delete apexcord.mod

Removed, this file is created upon compilation
Delete dwm_module.mod

Removed, this file is created upon compilation
Delete newmodel.mod

Removed, this file is created upon compilation
Delete vsh_basis_module.mod

Removed, this file is created upon compilation
Delete vshengine.mod

Removed, this file is created upon compilation
Merge pull request #112 from aburrell/develop

Develop: Improved usability of makefiles