Fix inspection results discussed in #67  - UrlShortener.java

Changes
-- Remove unused code
-- Fix unchecked call for Android AsyncTask execute() by specifying the generic types
-- Check for NPE
Fix inspection results discussed in #67 - UrlShortener.java (phase 2)

Changes
-- Bring back unused code (as seen in another pull request that its going to be required soon.)
-- Fix unchecked call for Android AsyncTask execute() by specifying the generic types
-- Check for NPE
Fix inspection results discussed in #67  - UrlShortener.java

Changes
-- Remove unused code
-- Fix unchecked call for Android AsyncTask execute() by specifying the generic types
-- Check for NPE
Merge branch 'source-inspection-fixes' of https://github.com/asagrawal/physical-web into source-inspection-fixes
Fix code inspection results discussed in #67 - UrlShortener.java (phase 3)
-Incorporate review comments:
-- Fix indentation
-- Change generic Object to String for AsyncTask string params
Fix code inspection results discussed in #67 - UrlShortener.java (phase 4)
-- remove extra line between imports
Refactor code for lengthening of short url's in URLShortener utility
Merge branch 'master' of https://github.com/google/physical-web
Merge branch 'master' of https://github.com/google/physical-web
Merge pull request #173 from schilit/master

Update library
Merge branch 'master' of https://github.com/google/physical-web
Merge branch 'master' into url_writing_fix
implemented beacon url writing updates
Merge pull request #174 from matthewsibigtroth/url_writing_fix

Url writing fix
Merge pull request #162 from asagrawal/source-inspection-fixes

Fix code inspection results discussed in #67  - UrlShortener.java

- Sorry I took so long, looks good!
Remove section 15.105b as not required
Versioning updates for latest release
Merge pull request #175 from matthewsibigtroth/updates_for_release

Versioning updates for latest release
Handling malformed urls
Merge pull request #177 from matthewsibigtroth/url_writing_url_prefix_fix

Handling malformed urls.
Quick-merging for London demo.