Reorganizing and major rewriting of Soundex module

* Deleted the soundex.charmap module and depend on silpa_common.charmap
  module.
* __init__.py doesn't contain any code
* Soundex algorithms are improved for efficiency and now fixes #1, which
  is related to commit charmap/3890568.
* Added tests for the module

close: #1

Signed-off-by: Vasudev Kamath <kamathvasudev@gmail.com>
Add travis integration