remove unused things.
test the base pipeline property.
add lxml as a new dependency.
test the html/xml pipeline properties.
test the url query property.
fix the non-zero boundary condition problem found on testing.
test the text response property.
remove unused code.
test the dinergate base class.
fix the wrong exception type found on testing.
add requests as a new dependency.
Merge pull request #5 from tonyseek/feature/test-dinergate-pipeline

Test the dinergate class and pipeline property