Add ServiceBuilder class

Add ServiceBuilder as a friend to ServiceConfiguration and Service.
Remove one Service constructor and make another private because of
ServiceBuilder.
Add tests for ServiceBuilder
Update Service tests to use ServiceBuilder
Fix typos in ServiceBuilder
Merge pull request #37 from Melzas/add-oauth2-servicebuilder

Add ServiceBuilder class
Add utility function, that extracts query parameters from URL
Expand ParameterList by adding function, that converts it to map

add getParametersAsMap function
add parameters_map_t typedef
Add TokenException class, that describes error, returned by server
Modify Token class, by replacing raw values with named constants

added constants EXPIRES_UNDEFINED and REFRESH_UNDEFINED
Add Service functions to parse parameters to token as described in rfc6749 section 5

Service::parseTokenResponse and Service::makeTokenError added
Implement OAuth 2.0 Service getAccessToken dependencies

getAccessTokenAuthCodeGrant, getAccessTokenImplicitGrant, getAccessTokenOwnerCredentialsGrant, getAccessTokenClientCredentialsGrant implemented
Add const modifier to ServiceBuilder setSendRequest parameter
Add tests of Service getAccessToken for all grant types