added API calls

new API calls for:
- getting user's contact info
- getting a list of tasks delegated to user
- getting a list of tasks delegated from user
- getting a list of shared workspaces
Merge pull request #20 from katyaa/master

new API calls for:

getting user's contact info
getting a list of tasks delegated to user
getting a list of tasks delegated from user
getting a list of shared workspaces