Changes

These functions are for performing checks for certain data being present. They can return True or False, throw RelaxWarnings, or raise RelaxErrors. === Packages === These functions are found in the pipe_control and specific_analyses packages: * pipe_control: The check_*() functions are located in the individual modules of this package.* specific_analyses: For these packages, a special 'checks' module should be created for these functions. === Design === The check_*() functions should have the 'escalate' keyword argument which can have the following values: * 0 - This will simply cause the function to return True or False.* 1 - In addition to returning True or False, the function will throw a RelaxWarning for better user feedback.* 2 - This will cause a RelaxError to be raised if the data is missing, not set up, etc. Otherwise the function returns True.