Fixes gh-1570
Cherry-picked from 0960908b and 258c6f11

Fixes gh-1548 again

Previously, EnableAutoConfigurationImportSelector assumed that it
would always find auto-configuration attributes from an
@EnableAutoConfiguration annotation. This assumption does not hold
true in certain circumstances, although exactly what those
circumstances are is unclear. It could occur if the import selector
were used directly, but it's package-private making that unlikey. In
such circumstances a NullPointerException was being thrown.

This commit asserts that the attributes are non-null and, should the
assertion fail, produces an error that is more helpful than an NPE.

Closes gh-1512

Closes gh-1522

Closes gh-1540

The fix for gh-1475 introduced the use of an artifact's group to
discriminate between two libraries with the same name (artifact id)
and version. However, in the case of Gradle, a group name was not
provided for libraries that have been resolved from a repository.

This commit updates ResolvedArtifactLibrary to use the group obtained
from the underlying ResolvedArtifact as its discriminator.

Fixes gh-1543

User can set those properties (optionally) to use a different
DataSource than the default.

Fixes gh-1558

When MVC path matchers are used as metric keys, they can still contain
invalid characters and patterns (like asterisks). This change removes
some more special characters and also tidies up the names a bit so
no key part starts or ends with "-" (which is ugly).

Fixes gh-1528

Protecting /error doesn't make a great deal of sense and if it is
protected you don't get the ErrorPageFilter for the attempt at loading
it, so Tomcat renders its own HTML error page (when deployed as WAR).

Fixes gh-1548

Fixes gh-1534

There was too much state really in the old implementation of
AuthenticationManagerConfiguration, and it was leading occasionally
to null pointers when method A assumed that method B had already
been called and it hadn't. This change manages to concentrate all the
references to an AuthenticationManagerBuilder into a single method
call, removoing the need for storing it at all.

Fixes gh-1556

The applicationDefaultJvmArgs property was added in Gradle 1.7. This
commit updates RunPluginFeatures to access the property defensively
so that the plugin can be used with Gradle 1.6.

Fixes gh-1511

Closes gh-1503
Closes gh-1505

Closes gh-1524

Closes gh-1510

Closes gh-1500

The loading is via a marker interface SpringBootAstTransformation
to avoid clashing with other services registered as org.groovy.*

Fixes gh-1392

Fixes gh-1488

Change SpringApplicationContextLoader to set active profiles using the
`spring.profiles.active` environment property rather than calling
`SpringApplication.setAdditionalProfiles`. This allows @ActiveProfiles
to replace existing profiles rather than add to them which is consistent
with the Spring TestContext Framework.

Fixes gh-1469

Allow customization of the Apache HTTP Client used in TestRestTemplate
via an options enum.

Fixes gh-1497

Update LevelRemappingAppender to that any calls that aren't remapped
are still logged.

Fixes gh-1481

Prior to this commit, the repackage goal silently ignored the case of
two libraries having the same name and version but a different group.
As a result, the second library was overwriting the first one in the
repackaged jar.

This commit adds support for custom Library names and updates the
Maven and Gradle plugins so that the name includes the group ID
when there would otherwise be a duplicate.

Fixes gh-1475

Fixes gh-1470

This commit clarifies the role of the 'addResources' flag and makes
it explicit that any duplicate found in the target directory are
actually removed

Fixes gh-1479

This commit is a workaround until git-commit-id-plugin 2.1.11 is
released. See also issue 124 of that project

Fixes gh-1484

Add additional constructor and a protected postProcessConverters method
to make it easier to manipulate the final converter list that will
be used.

Fixes gh-1482

Convert any session timeout values from seconds to minutes when
configuring Tomcat.

Fixes gh-1422