Merge pull request #300 from DigitalGlobe/feature/remove-alpha

Merge pull request #299 from DigitalGlobe/v1.2.0

Added Alpha band handling.

Some refinements to OSN's cmake setup, and reinstaing the release setup so that the build number is not included for releases.

Update version number on 1.2.0 branch

Update version number on 1.2.0 branch

Merge pull request #296 from DigitalGlobe/bug/no_pthreads

Add missing C language specifier so that the pthread check can pass on CentOS.

Merge pull request #295 from DigitalGlobe/feature/extra-fields

reset cli extraFields after a bad merge.

Merge pull request #294 from DigitalGlobe/feature/extra-fields

Post PR comments addressed from Ryan plus fixing the date field so that the actual date is written.

Post PR comments addressed from Ryan.

Avoid overwrite of extra fields in the case where a user has set them prior to OSN getting to that point.

Fix producer info flag and add support for extra fields.