add redirect uri to configuration

fix namespace issue of README
fix coding standard issue
add functionality to fetch an access token (from code)
Merge pull request #2 from Bigpoint/prototyp

Prototyp
add client credentials (grant type) support
set correct uri, content type, payload based on http method
Merge pull request #3 from Bigpoint/prototyp

Prototyp
refactor api
seperate headers in field and value
split header fields into field-name and field-value
add phpunit test setup
add header class to remove some functionality from curlclient
rename setHeader method of header class
fix codind standard issues
fix missing coverage report of phpunit
fix autoloading issue of testsuite
add flush functionality to header
remove absolute path from phpunit.xml
refactoring of response, request and curlclient (use header object)

add iterator interface to header
add unit test for header