Added EquipmentActions cross-ref

* Added EquipmentActions cross-ref table to Equipment schema, providing
the capability to have many equipment records associated with a single
Action.
* Deleted EquipmentID from Actions
* Added respective foreign keys
* Modified Equipment diagram to better illustrate changes
* Sorted field names in Actions to move Methods to 3rd field, right
below ActionTypeCV.  This is because a combination of ActionType and
Method define the action.
Removed EquipmentAction subclass tables

Removed all the extra EquipmentAction subclass tables that are no
longer necessary due to the implementation of the following features:
* ActionFileLink
* DataQuality.ReferenceMaterials
* ReferenceMaterialValues tables
* DataQuality.DerivedEquations (this is pending work on the
Provenance_FeatureBranch, which will fully enable calibration actions.)
Equipment Diagram & Documentation edits

* Rearranged tables in Core, Equipment and Overview diagrams to reflect
changes in Equipment.
* Updated ext_equipment.md to reflect changes
Change name of ODM2Samples schema to ODM2LabAnalyses

We now handle Samples (Specimens) in the SamplingFeatures Schema, and
Equipment and DataQuality.ReferenceMaterials in their respective
schema.  Therefore, the purpose of this schema has really morphed into
one that enables some remaining functions of Laboratory Information
Management Systems. Thus the rename.
Moved Directives to LabAnalyses schema

* Moved Directives table to newly renamed ODM2LabAnalyses schema (was
ODM2Samples).
* Adjusted ODM2Core, ODM2LabAnalyses and ODM2Overview diagrams slightly
* Removed SamplePreparationAction sub-class table, as it was no longer
necessary.
Modifications to Equipment schema and diagrams

1. I added the InstrumentOutputVariables entity back into the Equipment
schema. I need it for the Sensors extension.
2. I rearranged the Equipment diagram a little to show Variables and
Units connected to InstrumentOuputVariables.
3. I rearranged the LabAnalysis diagram a little for readability.
Removed DirectiveID from Actions

* Removed DirectiveID from the Actions entity.
* Created the ActionDirectives cross-reference table and a 1:1 (or 1:0)
relationship foreign keys to Actions.  This is how we dealt with
NormalizedByReferenceMaterialValueID in the Results table, and in a
database implementation that incorporated these optional schemas, those
foreign keys would go directly into Actions & Results.
* Slight rearrangement of LabAnalyses diagram, but this is not yet
complete.  Need to deal with AnalysisBatches.
Created LabAnalysis.SpecimenBatchLines

* Removed legacy AnalysisBatchActions and BatchSampleLines tables, in
order to replace them with a potentially simpler and more effective
approach that is now supported by ODM2.
* Created LabAnalysis.SpecimenBatchLines table and added a note to
explore the following idea:
  * If an Index or Key were made from concatenating SamplingFeatureID &
ActionID from the FeatureActionResult table, then it would be possible
to track the position of a Specimen within an AnalysisBatch as it
progresses from a SpecimenPreparationAction to an
InstrumentAnalysis[=MethodType] ObservationAction. This info is tracked
in nearly every lab.
  * For a SpecimenPreparationAction, where there are no Results and
ResultID is null, such a FeatureActionIndexID would be the same as a
primary key for the FeatureActionResult table (i.e. a
FeatureActionResultID).
  * For a InstrumentAnalysis[=MethodType] ObservationAction, however,
using a FeatureActionResultID will not work, because there can by many
results for each unique Specimen-Action combo.
Rmoved SpecimenBatchLines entity

Per Anthony’s recommendation, I removed this entity pending a new
LabAnalyses feature branch where we will explore how to implement what
is needed to describe these concepts.
Merge pull request #34 from UCHIC/Equipment_FeatureBranch

Merge Equipment feature branch into Master - there were also changes here to the LabAnalysis schema, but that schema is unfinished and needs to be fleshed out in a separate feature branch.