Updated to support Mambu model 3.2

- Use Mambu model 3.2
- Rename API output snapshot jar file to 3.2
- Add Centers API
- Removed workarounds for group pagination and clients filering (fixed
in 3.2)
Updated to support JSON APIs.  Added API wrappers for create Clients and Loans in Json API and getting Custom Fileds information API.

1.1. Added support for JSON content type for Mambu API requests. a)
Modified MambuApiServices, RequestExecutor , GsonUtils, APIData to
support additional  methods to specify the contentType in API requests,
specifying non-default date/time formats and generating API requests
with application/json content type.
b) Created LoanAccountExtended class ( in apisdk.model) to support json
object generation and parsing it to the format required by "Create
LoanAccount json API".

2.  Implemented API wrappers for creating Clients and Loans using json
format (ClientService and LoanService).

3. Implemented wrappers to support getting Custom Fields information
(can only be tested with Mambu 3.3).
Cosmetic changes as per recent pull request feedback comments
Cosmetic comment correction in DemoUtil
Merge branch 'master' of https://github.com/mdanilkis/Mambu-APIs-Java into mdanilkis-master

Conflicts:
	config.properties
	lib/Mambu-APIs-Java-3.2-SNAPSHOT-jar-with-dependencies.jar
	lib/Mambu-APIs-Java-3.2-SNAPSHOT.jar
	src/com/mambu/apisdk/services/AccountingService.java
	src/com/mambu/apisdk/services/ClientsService.java
	src/com/mambu/apisdk/services/OrganizationService.java
	src/com/mambu/apisdk/util/RequestExecutor.java
	src/com/mambu/apisdk/util/RequestExecutorImpl.java
	src/demo/DemoTestClientService.java