Merge pull request #404 from bnmurphy/emissctrl_default

Minor updates to resolve missing emissctrl file and header text

CMAQv5.2.1

Minor release will be made available on March 14, 2018
Resolves several bugs and issues. Adds some minor documentation.
Release notes descriptions are available in CCTM/docs/

Fixed link to documentation.

A number of bug and feature fixes have been introduced such as bounda…

…ry and initial aerosol condition checking, minor chemical mechanism updates and memory management error solutions.

CMAQv5.2Beta includes a wealth of updates, particularly for modeling …

…dust and organic particulate matter. There are also important updates for upper atmosphere ozone prediction and chemical mechanism definitions. As we proceed to the final release of CMAQv5.2 (June 2017), we will release further version of the experimental model so that the community can take advantage of solutions to issues as they are solved and incorporated.

Make v5.1 as previously released by CMAS, for an EPA public release t…

…o set up a DOI

CMAQ version 4.7.1 official release