Removed Codes & Names from Specimens & Sites

* and added SamplingFeatureCode
* also removed SRSID from SamplingFeatures, because it is redundant
with info contained in Geometry
Moved Elevation_m & ElevationDatumCV to SamplingFeatures

* Was in Sites, but after *long* discussion we realized the need for
some Specimens to have their own Elevation info without being a child
to a Site.
* Deleted Note that we Recommend that all Specimens are children to
Sites.
Merge pull request #36 from UCHIC/SamplingFeatures_FeatureBranch2

Merge SamplingFeatures feature_branch2