Polish Javadoc for embedded database support
Improve configurability of EmbeddedDatabaseBuilder

This commit improves the configurability of EmbeddedDatabaseBuilder by
exposing the following new configuration methods.

 - setDataSourceFactory(DataSourceFactory)
 - addScripts(String...)
 - setScriptEncoding(String)
 - setSeparator(String)
 - setCommentPrefix(String)
 - setBlockCommentStartDelimiter(String)
 - setBlockCommentEndDelimiter(String)
 - continueOnError(boolean)
 - ignoreFailedDrops(boolean)

If more fine grained control over the configuration of the embedded
database is required, users are recommended to use
EmbeddedDatabaseFactory with a ResourceDatabasePopulator and forego use
of the builder.

Issue: SPR-11410