-Added select by meta data functionality

-the ' char is now properly escaped when building sql statements
-the sql script templates where updated to include ' when enclosing a text
value
-a test was added to test adding a song with an ' character

-added functionality to get songs given a list of ids

-refactored the DBTest class. Each type of test is called in it's own
function now

-defined the beginnings of the plugin interface