Fix #1522

Using MERGE on patterns larger than single nodes requires
at least one bound node to be valid. This commit throws
and understandable error for this case
Prohibit equality comparison of incomparable values

o This ensures that nodes can only be equality compared against nodes, and relationships only against relationships
   (particularly prohibits comparing entities against map parameters)
fix udc_host IP resolution
Improved data provided by AvailabilityGuard to help debugging.
Merge pull request #1565 from jexp/fix_udc_host_ip_resolution

fix udc_host IP resolution
Merge pull request #1548 from systay/1522

Fix #1522
Merge pull request #1559 from boggle/2.0-incomparable-values

Prohibit equality comparison of incomparable values
Refactors MERGE to be handled by as an UpdateAction instead of as a Pipe
Allow MERGE to run inside FOREACH
Fix problems with CREATE for relationships without declared nodes

When doing a CREATE with a relationship where the end nodes
have not already been declared, the old code would add node
creation to the execution plan. This was, however, buggy, and
for some situations, especially surrounding FOREACH, the code
ended up creating much too many elements.

Fixes error handling of erroneously provided lush nodes.

Also changes all bare fields into methods.
Verify that pretty graph doc tests update the graph correctly
(i.e. create the correct number of nodes, relationships, etc.)
Move the server chapter into the operations part.
Move the server operations sources into the ops/ directory.
Reduce the information about the web ui to the bare minimum.
Update to doctools version 15 to fix a graphviz issue.
Proper passing of Monitors, as intended by the author
Fix docs spelling mistake.
Fix issue when mixing Cypher queries of different versions

If the same query ran first using version 1.9 and then 2.0,
an exception was thrown.