fix test for identical controls to not give a warning
add simple test for entropy optimizer
add single-dimensional test example
convert line endings to Unix
support fitting one-dimensional problems (where only group-level controls are given)
add failing example for entropy fitting
compute IPG
refactor: loop over names and not list items
prepare controls with intercept (omitting -1 in the formula), and with suffix if it's a group or individual control
refactor: extract function
also rename intercept column, because actually both group-level and individual-level intercepts are usually controlled for
really need to remove controls with only one level, otherwise error: 'contrasts can be applied only to factors with 2 or more levels' in one of the tests
Properly support multiple controls at individual or group level

- Use intercept and interactions with all effects of lower order in model matrix
- Detect conflicting control totals
- Tests