Enhanced test cases for similarity measures and tokenizers by splitti…

[rishab93]

…ng the test cases for each similarity measure and tokenizer in a separate file.

Steps Followed to make these changes:

1. Made a separate file for test cases of each similarity measure, and moved the test cases of that similarity measure from test_simfunctions.py to that particular file.
2. Removed the file test_simfunctions.py after moving the test cases of each similarity measure to a separate file.
3. Made a separate file for test cases of each tokenizer, and moved the test cases of that tokenizer from test_tokenizers.py to that particular file.
4. Removed the file test_tokenizers.py after moving the test cases of each tokenizer to a separate file.
5. Ran nosetets successfully.
6. Committed on local branch.
7. Raised a pull request.

[coveralls]

Coverage decreased (-6.4%) to 93.588% when pulling a45a211 on rishab93:enhan_test_files into b568b6b on anhaidgroup:master.

[coveralls]

Coverage remained the same at 100.0% when pulling e245997 on rishab93:enhan_test_files into b568b6b on anhaidgroup:master.