Additional wrappers for Tasks, Documents and Organization services

1. RequestExecutor
- added support for DELETE method

2.  Tasks
- added getTasks() by clientId, username, task status
- added deleteTask() by id

3. Organization
- additional methods to get lists of Branches and Centres with full
details (primarily needed to have addresses)

3. Documents (Demo only)
- added test to upload a document from a file
- added encoding helper method
- added test/data directory to place files for uploading

4.  DemoUtil
- moved some good patterns for getting demo data (found in Tasks) into
DemoUtil helper methods (getDemoUser() and getDemoClient())

5. test/data directory
- added 'data' under test (test/data) to place temp files for upload
testing
Revert "Additional wrappers for Tasks, Documents and Organization services"

This reverts commit c55b6b0b9e859427b6c3b75dbea49f041ef4d986.
Additional wrappers for Tasks, Documents and Organization services

Additional wrappers for Tasks, Documents and Organization services

1. RequestExecutor
- added support for DELETE method

2.  Tasks
- added getTasks() by clientId, username, task status
- added deleteTask() by id

3. Organization
- additional methods to get lists of Branches and Centres with full
details (primarily needed to have addresses)

3. Documents (Demo only)
- added test to upload a document from a file
- added encoding helper method
- added test/data directory to place files for uploading

4.  DemoUtil
- moved some good patterns for getting demo data (found in Tasks) into
DemoUtil helper methods (getDemoUser() and getDemoClient())

5. test/data directory
- added 'data' under test (test/data) to place temp files for upload
testing
Added getImage() API and updated TasksService

- Added getImage API to retrieve image files from Mambu
(DocumentService)
- updated createTask() to use JsonTask object
- commented out unit test for createTask() until mikoto issue with
extracting result is resolved.
- updated corresponding demo programs and APIData
Corrected previously submitted DemoUtil to again contain Mambu demo data
Updated RequestExecutorImpl to support appKey for Json requests

1. Updated RequestExecutorImpl to support appKey for Json (as per
MBU-3892 fixed in 3.3 release)
2. Updated DELETE method to support appkey
3. Added some more helpers to get demo data in DemoUtil
Updated to address review comments for pull request #25

Misc cosmetic and readability enhancements
Merge pull request #25 from mdanilkis/master

Additional wrappers for Tasks, Documents and Organization services