Make sure ErrorPageFilter is only applied once per request

Fixes gh-1257
Merge branch '1.1.x'
Upgrade to Spring 4.1.0 and use Yaml support that migrated from Boot

Closes #813
Fix HTTP status code mapping in HealthMvcEndpoint

refs #1264
Flexible registration of additional PublicMetrics

This commit permits the use of several PublicMetrics instances by
default. Previously, only one PublicMetrics service could be specified
and a user configuration would remove all the defaulting.

VanillaPublicMetrics now takes a collection of PublicMetrics and
invokes them in sequence to build the final collection of metrics.
The system-related metrics have been moved to SystemPublicMetrics and
are registered by default.

Also updated the documentation to mention this feature and how it
could be fully overridden.

Fixes gh-1094
Polish and re-add author name
Correct the default Logback config location in the documentation

Fixes #1247
Merge branch '1.1.x'
Fix typo (fixes gh-1273)
Reverse priority of property sources when extracting sub properties

Fixes gh-1259
Ensure custom HTTP code mappings for /health don't remove default mappings

Previously any custom http code mapping would remove the default mappings. With this commit the behaviour is changed so that default mappings will stay if a custom mapping is registered. Certainly a default mapping can be overridden.

fixes #1264
Documentation update

This commit fixes some inconsistent or outdated keys in the
documentation. More specifically:

* allowSessionOverride is no longer a template parameter
* templateEncoding has been renamed to charSet
* Groovy templates do not have the same configuration hierarchy, hence
  they don't share all settings
* spring.data.elasticsearch.local does not seem to exist
* flyway prefix and suffix should be sqlMigrationPrefix and suffix
* spring.rabbitmq.virtualHost had a typo
* endpoints.error.path is not a valid property
* shell.command-path-patterns had a typo
* spring.datasource.max-wait had a typo

Fixes gh-1226
Add java options for Heroku Procfile

Added $JAVA_OPTS variable to the sample Heroku Procfile.
If this is left out it can cause memory issues when the app starts.

Fixes gh-1266
Ensure custom HTTP code mappings for /health don't remove default mappings

Previously any custom http code mapping would remove the default mappings. With this commit the behaviour is changed so that default mappings will stay if a custom mapping is registered. Certainly a default mapping can be overridden.

fixes #1264
Use class name not value to support non-Hibernate JPA vendors

With this change I got a simple Eclipselink version of the data-jpa
sample working. I'll push that when I get time to research it a bit more
(I needed to set up a Java agent so either that might be a problem
for our integration tests if we can't work around it).

Fixes gh-1268.
Merge branch '1.1.x'
Correct the profile name in Travis configuration
Merge branch '1.1.x'
Correct the descriptions of two sample projects
Merge branch '1.1.x'