Use value with resolved placeholders in all cases
Update Boot plugin to latest snapshot

This enables us to add a classifier to the bootRepackage task and
have spring-xd-dirt spit out its own executable jar. Also validates
that 1.1.2 is going to work in other ways.

Remove spring-xd-exec project (dirt has exec jar now)
XD-1870 Rabbit modules now use addresses

* Remove host and port from RabbitConnectionMixin, RabbitSource & RabbitSink
* Added addresses to RabbitSource & Sink
* Updated Rabbit Acceptance Test.
XD-1788: Validate deployment props
Prevent deletion of content.

Previously, if two opening fences were encountered, no failure was
reported.
XD-1848 more fine grained states via REST API

The status of a stream, as returned by the REST API (and thus the shell also),
may now contain any of the following states:

* deploying (deployment has been initiated)
* deployed (fully deployed based on each of the stream's modules' count properties)
* incomplete (at least 1 of each module, but 1 or more of them not at requested capacity)
* failed (1 or more of the modules does not have even a single instance deployed)
* undeployed (intentionally undeployed, or created but not yet deployed)
XD-1760 Enabling Short Circuiting

Now checking deployment property values and setting the "shortCircuitAllowed"
producer property if the following conditions are satisfied:
1. producer module is not partitioning
2. producer module's count is 0
3. next module's count is 0
4. both producer module and next module have the same criteria (both can be null)

Added "shortCircuiting" tests to AbstractDistributedTransportSingleNodeStreamDeploymentIntegrationTests

RabbitSingleNodeStreamDeploymentIntegrationTests and RedisSingleNodeStreamDeploymentIntegrationTests
now both extends from AbstractDistributedTransportSingleNodeStreamDeploymentIntegrationTests

Addressed PR comments, and rebased
XD-1839: Named channels only allowed in full streams
XD-1751 Connection Pool settings for jdbc modules

* Includes common pool settings as well as tomcat enhanced attributes
* Initial size is set to zero vs. the default of 10.
* Jdbc Unit has a test for testOnBorrow setting.
* hdfsjdbc, jdbchdfs & filejdbc testing will be covered by acceptance tests
* Code Polishing
Jdbc Connection pool settings now set via yml

Originally the PR used JDBCConnectionPoolMixin in order to set the connection pool settings.  However this proved to be a bit overwhelming for users when trying to setup a jdbchdfs, hdfsjdbc,filejdbc or filesink.
Now the pool setting will be setup via a servers.yml and application.yml
Connection test for shell was removed.

No longer valid, because settings will be established via the .yml files.
Conn Pool Config consolidated to one location in yaml

* Servers.yml
* application.yml
JdbcConnectionPool metadata is now available.

1) Add key datasource and pool variables in servers.yml
2) Add commented out section of datasource and pool variables in modules.yml as an easy way to customize the datasource used for modules but not for the XD infrastructure
3) For any modules that use jdbc functionality, add something like maxIdle = ${spring.datasource.maxIdle} into that module/job property file.
4) investigated to see if there was a way to inject a common snippet of connection pool xml into jdbc.xml, hdfsjdbc.xml, jdbchdfs.xml & filejdbc.  There was no smooth way to do this.