Update package.xml

Updated the version to 31.0
changed the version of files to 31.0. Removed Limit fieldDescribe and
ChildRelationship describe as it is not supported after version 30.0.
Added compound address fields to field to whitelist and fixed failing
testcases

Conflicts:
	apex-sobjectdataloader/src/package.xml
Update SObjectDataLoader.cls
Update SObjectDataLoaderTest.cls

Fixed Limit exception testcase as limits removed for field and childrelationship describe after version 30
Merge pull request #6 from Sonal4J/master

Updated code to handle compound Fields