Add @ComponentScan documentation

This commit provides a proper documentation for the @ComponentScan
annotation as a java config alternative to <context:component-scan/>

Issue: SPR-11846
Fix method comment for getRequiredProperty(String)
Merge pull request #544 from kryger/patch-1

* patch-2:
  Fix method comment for getRequiredProperty(String)
PathMatching options:configure all HandlerMappings

Since SPR-11486 and SPR-10163, Path Matching options can be configured
to customize path matching options for RequestMappingHandlerMapping.
Prior to this commit, the defined pathMatcher and pathHelper instances
were only used in RequestMappingHandlerMapping.

This commit now registers pathMatcher and pathHelper beans under
well-known names and share them with several HandlerMappings beans,
such as ViewControllerMappings and ResourcesMappings.

Issue: SPR-11753
Fix "**" precedence in AntPathMatcher comparator

Prior to this commit, "**" and "*" pattern elements had
the same priority when comparing two patterns.
So when comparing several patterns, the computed order was:
1- /hotels/{hotel}/bookings/{booking}
2- /hotels/**
3- /hotels/{hotel}/bookings/{booking}/customer/{customer}

This commit updates the comparator so that patterns ending
with "**" (a.k.a "catch-all" patterns) are less specific than
the others; in the previous example, the 2nd pattern would
then end up last.

This commit also optimizes the comparator implementation.

Issue: SPR-6741
Further encapsulate AntPatternComparator$PatternInfo

Issue: SPR-6741
Rollback AntPathMatcher behavior for ".*" comparisons

Prior to this commit, AntPathMatcher had been refactored for SPR-6741.
During that process, a key feature has been removed:
When comparing two patterns, pattern elements (*, {}, etc) are counted
to score those patterns. When a pattern ends with ".*", the ending
wildcard should not be counted against pattern elements for this
pattern.

This commit reintroduces that behavior.

Issue: SPR-6741
Upgrade to Undertow 1.0.15 and fix failing test

Issue: SPR-11777
Check X-Forwarded-Host in ServletUriComponentsBuilder

Issue: SPR-11855