updates copyright year

Merge pull request #8 from harsh-biztech/update-authtoken-if-already-…

…existing-in-system

Fixes to update token values if already exists

Merge pull request #7 from harsh-biztech/update-authtoken-if-already-…

…existing-in-system

Update token values if already exists

Merge pull request #4 from jay-biztech/update_xero_php_oauth2_version

Update official Xero PHP SDK package

Update README.md

Merge pull request #2 from ishan-biztech/release/0.1.3

Version 0.1.3 release changes

Get scope from configuration file

Add homepage, support fields in composer.json

Add LICENSE file