Adding changes from last commit on custom-page branch - I want to get ONLY these changes into the master branch - there's probably a better way to do this...

Extracted JS and CSS sections into new files 'BaseJS.vm' and 'AppJS.vm' so they can be included in other templates without other unnecessary scripts and stylesheets; Created new 'Basic.vm' layout with no XNAT content and 'Content.vm' as a container for XNAT data available through Velocity that can be retrieved via AJAX without pulling in conflicting scripts and stylesheets; Added sample templates 'Basic.vm' and 'Blank.vm' for use with the 'Basic' and 'Content' layouts respectively.

Adding files for custom page feature, including skeleton for the admin page.

Minor fixes and updates: strip leading and trailing slashes from custom page name in url hash or query string; removed rogue semicolon; added methods to render and retrieve table HTML using XNAT.table(); added usage comment in 'hello.vm'.

Added fail-safe defaults to DatabaseConfig. Removed SpawnerConfig but added reference to spawner library SpawnerConfig to WebConfig. Added /xapi path to Swagger configuration. Added mavenLocal() to publishing repositories in build file.

Moving Theme redirection and script/style page imports to htmlOpen.vm for better coverage instead of HeaderIncludes

New and updated files for custom page support. Put page content files in *templates/pages or in the '/pages' folder at the root of the web app. Velocity, JSP, and HTML files are supported.

Moving ThemeService interface, implementation and ThemeConfig to XDAT core project and updating references to new packages in other dependencies that had to move as well.

Added support for initializing site URL from request URL and servlet context. Finished StringUtils migration. Added XapiRestController handling.

Merge commit '37317f9f'

# Conflicts:
#	.gitignore
#	build.gradle
#	src/main/java/org/nrg/xdat/om/base/BaseXnatDicomseries.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatExperimentdata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatImageassessordata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatImagescandata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatImagesessiondata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatProjectdata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatPublicationresource.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatPvisitdata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatReconstructedimagedata.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatResource.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatResourcecatalog.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatResourceseries.java
#	src/main/java/org/nrg/xdat/om/base/BaseXnatSubjectdata.java

serializer service rather than separate object mapper instances.
Integrated spawner functions. Moved from using resource resolver
directly to using XnatResourceLocator.

Fixed function name.