Update code to make the test green.

The updated code need refactoring as it contains duplicated code.
* Update the COMMON_LICENSES list
* Add a new function to get the dje_license_name
* Did a surgery in the function generate_attribution to restore the
license summarization features + commented out all the non-useful code
* Add code to check if the provided template_location exist/valid.
* Update the default template to support license summarization
* Update some test code
Fixed #145 - Add code to test is the provided api_url valid or not.
Fixed #148 - input dir path doesn't need to end with '/'
Removed a lot of dead code and code that related to multiple licenses.
Fixed #150 - Add error handling code to avoid writing empty value to the
attribution file
Some comments clean up
Add code to print the cause of error.
a temp commit to remove all the code that related to multi-license
support. Note that it's not completed and there is error in it.
Very minor code change to make the test green
Remove the dead code.
Create test code.
Fixed #152 - Log error when multiple licenses are detected. In addition,
this commit also removed some dead code and comments.
A temp fix for #113 and #153
Specification v 1.0
Update the SPEC version and remove the 'license_text' and 'notice' field
Fixed #113 and #153 by using the expanduser from os.path