Merge pull request #1228 from jtruesdal/add_gx1v7

Add gx1v7
Adds support for gx1v7 grids for cesm. In gx1v7 (1 degree ocean) the Caspian is removed from the ocean domain and added to the land domain.

Test suite: regression testing passed
Test baseline:
Test namelist changes:
Test status: [bit for bit, roundoff, climate changing]

Fixes [CIME Github issue #]

User interface changes?: Added new aliases for resolutions supporting a gx1v7 mask (Caspian in land domain). In addition to adding a gx1v7 version of existing gx1v6 grid aliases, I also added new aliases with a mask acronym in cases where the ocean mask was undefined. For example the resolution f09_f09 has an implicit gx1v6 mask but I added two new aliases making the mask explicit.
f09_f09_mg16
f09_f09_mg17
I also added the new mapping and domain files for gx1v7.
Eventually we may deprecate the aliases with undefined ocean masks but for now I left the implicit gx1v6 versions for backwards compatibility.

Code review: Jim and Mariana