Implement some functionality in query.cpp
More documentation fixes
Fix nonstandard xvalue to lvalue conversion
Change from shared to unique pointer
Delete missing state.h
Move schema and model to exposed
Separate and rename task model with task builder.
Change to operator overloading
Documentation :love_letter:
Add test cases for constructing query
Remove redundant Query base class
Update documentation
Boost gregorian for deadline
Remove default ctor/dtor
Move using to unit test namespace
Refactor query_tests.cpp
Use unique_ptr from the beginning for safety
Revive Query base class, rename it to Query::Any
Change Haskell style comma to C++ style
Merge pull request #58 from evansb/implement-task-model

Implement basic actions