Updated to support Mambu's 3.4 new APIs and enhancements

1. Updated to use 3.4 model jar
Updated target  name to be: Mambu-APIs-Java-3.4-bin.jar

2. Add Wrappers for new APIs;
ClientService: UpdateClient
LoanService: Update LoanAccount

SavingsService:
a) Update Savings Account
b) Approve Savings Account
c) Delete Savings  Account
d) Close Savings Account

3. Search service:
Removed offset param. It’s not used in search API.

4. Updated Request Executor:
Added charset=UTF-8 to Json content header.  MBU-4137 is now fixed to
handle UTF-8 in jsons

5. Logger:
Wrapped Logger calls with a check for Logging Level  (e.g
isLoggable(Level.INFO))  for better memory management
Even when info logging is not enabled - Java Logger still creates the
strings needed for the logging. Some of these strings are huge
(especially for image/document API) and this effects memory consumption

6. URLHelper:
Added URL encoding to the URL string (see fixed MBU-4669 Unable to
retrieve objects that have IDs with spaces or UTF 8 characters, via
API,
Also removed no longer needed verification for spaces in IDs (IDs can
have spaces now in API requests)

7. Demo:
Added test methods for new APIs

8. Verified miscellaneous API Issues fixed  in Mambu:
a) MBU-4210  - Address is not returned with a Create Client request.
OK now
b) MBU-4581 User Permissions object is included with getUserDetails.
Verified.
c) Tested Creating Loan account with guarantors and assets: Creation
Ok.  Get LoanDetails doesn’t return guarantor details

9. Added TODOs for fixing some API issues in Mambu.
Updated to address pull request #26 review comments

Updated as per review comments.

Also modified the usage of the Logger in RequestExecutorImpl.java:
moved main logging calls into the private methods and enhanced logging
to exclude unneeded data from being logged.
Updated to reference Mambu 3.4 files
Updated DemoUtil to use demo account
Updated with review comments #2 for Pull request #26

Reversed back to IllegalArgumentException in Savings Service
Modified format for truncated encoded data
Log exception and return “” in URlHelper if it fails to parse Url.
Merge pull request #26 from mdanilkis/master

Updated to support Mambu's 3.4 new APIs and enhancements