Fix logic for identifying test classes on Windows

Use File.separator rather than hard-coding the use of ‘/‘

Closes gh-1571
Merge branch '1.1.x'
A few tweaks that might improve performance on startup

... or couldn't hurt anyway.

1. Extends the definition of a web application for @ConditionalOnWebapp
so that a StandardEnvironment can be used (cutting out JNDI failures
for Environment properties)

2. Doesn't bother using StandardServletEnvironment in integration tests

3. Make the NON_ENUMERABLE_ENUMERABLES in PropertySourcesPropertyValues
static so they only get initialized once (not a huge issue at all)
Merge branch '1.1.x'
Add version properties for banner.txt usage

Extract banner.txt logic to ResourceBanner and include support for
`spring-boot.version` and `application.version` properties.

Fixes gh-1586
Formatting
Merge branch '1.1.x'
Fix description of test file to be tests.groovy

Corrected the documentation to refer to file as tests.groovy, rather
than test.groovy. Updated cope snippet as tests.groovy should expect
"Hello World!" rather than "Hello World".

Closes gh-1593
Merge branch '1.1.x'
Activate WebSecurityEnabler only for web applications

Done in order to align with the rest of the configuration. Absent this
check, the bean will be installed in non-web applications without the
corresponding dependencies, causing the bootstrap to fail.

Closes gh-1588
Merge branch '1.1.x'
Update docs with DispatcherType.ERROR for filters

Some frameworks handle all requests in a Filter, so you have to
explicitly register it as an ERROR dispatcher.

See gh-1272
Merge branch '1.1.x'
Fix typo in comment

Closes gh-1596
Merge branch '1.1.x'
Add tests to verify that ActiveMQAutoConfiguration backs off

See gh-1599
Merge branch '1.1.x'

Redundant @ConditionalOnMissingBean annotation has been removed.
ActiveMQConnectionFactoryConfiguration is not auto-configuration and
is imported by ActiveMQAutoConfiguration which is protected by
@ConditionalOnMissingBean(ConnectionFactory.class)
Detect startup failures in additional Tomcat connectors

Previously, only the state of the primary connector was checked when
verifying that the embedded Tomcat instance has started successfully.
This commit updates the verification logic to examine all of the
service's connectors, thereby also detecting startup failures of any
additional connectors the have been configured.

A check on the primary connector's state has been removed from
initialize as, at this stage, its state will always be NEW.

Fixes gh-1591
Merge branch '1.1.x'
Polish formatting