Fix broken documentation links

Fix links to `actuator-noweb`, `actuator-log4j` and `hornetq` samples.

Fixes gh-1613
Make Thymeleaf @ConditionalOnWebApplication

If user creates a Thymeleaf app with a parent-child context then the
child should contain all the web-specific pieces (and they are likely
to fail fast if they need to be ServletContextAware, or slower if they
try to locate a WebApplicationContext at runtime). This can't happen
if the view resolver is being added to the parent.

Freemarker and Velocity already have similar tests because it is assumed
that they should be usable outside a web app, so this change just does the
same for Thymeleaf.

Fixes gh-1611
Copy server customization to management context

If the actuator endpoints are configured on a different port then there
are some settings in the main ServerProperties that we would like to
re-use (e.g. the access log). The easiest way to do that is to just
configure the management server using the same ServerProperties instance
and then overwrite the things that are different (and stored in
ManagementServerProperties).

Fixes gh-1581
Merge branch '1.1.x'
Tidy some Javadocs
Merge branch '1.1.x'
Fix failing ThymeleafAutoConfigurationTests

Remove accidental addition of a 1.2 test.
Merge branch '1.1.x'
Restore ThymeleafAutoConfiguration test

Restore the test removed during the merge.
Update ErrorPageFilter so it won’t try to forward a committed response

In some scenarios, the ErrorPageFilter will want to forward the request
to an error page but the response has already been committed. One common
cause of this is when the filter’s running on WAS. WAS calls
flushBuffer() (which commits the response), upon a clean exit from a
servlet’s service method.

Previously, the filter would attempt the forward, even if the response
was committed. This would result in an IllegalStateException and a
possibly incomplete response that may also have an incorrect status
code.

This commit updates the ErrorPageFilter to check to see if the response
has already been committed before it attempts to forward the request to
the error page. If the response has already been committed, the filter
logs an error and allows the container’s normal handling to kick in.
This prevents an IllegalStateException from being thrown.

This commit also updates the response wrapper to keep track of when
sendError has been called. Now, when flushBuffer is called, if
sendError has been called, the wrapper calls sendError on the wrapped
response. This prevents the wrapper from suppressing an error when the
response is committed before the request handling returns to the error
page filter.

Closes gh-1575
Merge branch '1.1.x'
Drop protocolHeader and remoteIpHeader defaults

The `protocolHeader` and `remoteIpHeader` no longer have default values
and must be opt-in.

Fixes gh-1624
Add `server.tomcat.port-header` support

Update Tomcat ServerProperties to support the RemoteIpValve portHeader
property.

Fixes gh-1616
Merge branch '1.1.x'
Add missing @since tag
Polish
Merge branch '1.1.x'
Next development version
Fixup version numbers following release
Merge branch '1.1.x'

Conflicts:
	all pom.xml files