enhance "names" request with optional "Recursive", "LeafOnly", and "ShowTags" parameters

This change adds support for the following additional and optional
parameters to the NameWikiPageResponder:
* Recursive: prints also sub-, sub-sub-, ... pages
* LeafOnly: in combination with "Recursive" prints only leaf pages that
don't have further children
* ShowTags: prints the tags associated with a page in []-brackets, e.g.,
[hello][world]

Sample outputs:

with "LeafOnly" enabled:
CoordSysSuite.CreateCoordSysTest
CoordSysSuite.CreateCoordSysTransformTest
CoordSysSuite.ReprojectionTest
ExpressionValidationSuite.ExpressionFilterValidationTest
ExpressionValidationSuite.ExpressionValidationTest
ModelSuite.ModelCreationTest
ModelSuite.ModelRasterDataImportSuite.BlueMarbleTest [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.DenverTest [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.EssenTest [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.FribourgTest [slow][win_only]
ModelSuite.ModelVectorDataImportTest
RasterDataSuite.LoadTerrainGridTest
RasterDataSuite.LoadTerrainTextureTest
RasterDataSuite.RasterDataImportTest [win_only]

and without:
CoordSysSuite
CoordSysSuite.CreateCoordSysTest
CoordSysSuite.CreateCoordSysTransformTest
CoordSysSuite.ReprojectionTest
ExpressionValidationSuite
ExpressionValidationSuite.ExpressionFilterValidationTest
ExpressionValidationSuite.ExpressionValidationTest
ModelSuite
ModelSuite.ModelCreationTest
ModelSuite.ModelRasterDataImportSuite [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.BlueMarbleTest [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.DenverTest [slow][win_only]
ModelSuite.ModelRasterDataImportSuite.EssenTest [slow][win_only]
ModelSuite.ModelVectorDataImportTest
RasterDataSuite
RasterDataSuite.LoadTerrainGridTest
RasterDataSuite.LoadTerrainTextureTest
RasterDataSuite.RasterDataImportTest [win_only]

Notes:
1) I don't have much experience with Java, which means that there might
be more effective ways to implement the stuff
2) I don't know if there are guidelines for naming the parameters (e.g.,
starting with a lower case letter)