Fix getTableNames bug on empty database

When function "getTableNames" is called on a empty database, an error occured "Undefined variable: tableNames"
Merge pull request #103 from neilime/patch-1

Fix getTableNames bug on empty database
Introduce IYamlParser for parsing YAML with an arbitrary library and use it in YamlDataSet. (Fixes #104)
Move the new YAML class and interface into their own files.
Merge pull request #105 from yparghi/iyamlparser

Introduce IYamlParser for parsing YAML with an arbitrary library and use...
Merge pull request #1 from sebastianbergmann/master

Merge At my end