Allow custom PersistenceUnitManager with JPA

Allow JPA auto-configuration to use an optional custom
PersistenceUnitManager defined as a bean.

Fixed gh-238
Fix typo in howto
Add docs for @EntityScan and JPA repository packages

Fixes gh-200
Add basic integration tests for the CLI

Add integration tests for the CLI that invoke it as a user would, i.e.
via the shell script in the package's bin directory.
Move CLI integration tests into spring-boot-cli

Use `maven-failsafe-plugin` to run CLI integration tests as part of
the `spring-boot-cli` project, removing the need for
`spring-boot-cli-integration-tests`.
Use @Autowired AuthenticationManagerBuilder

Update documentation to use @Autowired AuthenticationManagerBuilder.

Fixes gh-244
Upgrade various 3rd-party dependencies
Upgrade CRaSH shell to 1.3.0-beta14
Upgrade to Groovy 2.2.1

Fixes gh-126
Upgrade to Hibernate Validator 5.0.2

Update Hibernate Validator dependency to 5.0.2 and also include
Tomcat Jasper dependency. Jasper is required as it provides the
default ExpressionFactory implementation class
(org.apache.el.ExpressionFactoryImpl) which is indirectly
instantiated by Hibernate Validator.

Fixes gh-173
Upgrade to Tomcat 7.0.50

Upgrade to Tomcat 7.0.50, working around the potential
NullPointerException by also adding dependencies to
tomcat-embedded-jasper (which is now also required for Hibernate
Validator 5.0, see commit 377953babd3dcd15b6a29b13ae7882e88253a926)

Fixes gh-245
Upgrade version to 1.0.0.BUILD-SNAPSHOT

Fixes fg-243
Polish
Revert "Upgrade to Tomcat 7.0.50"

This reverts commit 3d60696b9bab750b7a773a3012e7756f3aeebe67.
Revert direct dependency on Jasper pending changes in Tomcat
Add some clarifications to maven plugin README

Fixes gh-246
Special case for YAML ParseException caused by bad document boundary

YAML documents can be text literals, so some common typos can be misleading
and not generate the expected exception (Boot fails to cast the
document to a Map, rather than reporting the underlying exception).

Fixes gh-235
Tweak javadocs in SprinApplicationBuilder
Make some dependencies optional
Strip trailing whitespace