mildsvm 0.4.1

Fix documentation to address CRAN NOTEs
Minor updates to functions, snapshot tests, and Github actions to accomodate newer versions of other packages (in particular, dplyr, tibble, testthat)

v0.4.0

Add omisvm() for ordinal multiple instance support vector machine
Add mior() for multiple instance ordinal regression
Add misvm_orova() for MI-SVM reducing ordinal to binary one-vs-all classification
Add svor_exc() for support vector ordinal regression with explicit constraints

Breaking: change generate_mild_df() to a new interface
Breaking: change mildsvm() to mismm()
Breaking: fix S3 method issue, affects mi_df and mild_df methods parameter
Add mi_df() class and methods, including as_mi_df()
Add method for mi_df objects for misvm(), cv_misvm() and all new ordinal methods
Add ordmvnorm data for examples
Add print methods for kfm_exact, kfm_nystrom, mild_df, mior, misvm, mismm, misvm_orova, omisvm, smm, svor_exc
Package now depends on R > 3.5.0, new imports of pillar, utils
fix warning when misvm() has matrix passed
fix .reorder() ambiguity
pass lintr checks
re-work internals for easier testing

Add new method to mildsvm(): method = ‘qp-heuristic’. This works similar to the method of the same name in misvm(), but uses the SMM kernel from kme() in the underlying calculations.
Fix bug in classify_bags() when using factors

The main modeling functions (misvm(), mildsvm(), and smm()) now have three methods:
- Formula method (i.e. misvm(mi(y, bags) ~ x1 + x2, data = df, …))
- Data-frame method (i.e. misvm(x, y, bags, …))
- Method for the mild_df class (I.e. misvm(mil_data, …)). This method often performs non-trivial aggregation or transformation since misvm() and smm() work naturally on MIL data and supervised data, respectively.
Prediction on main modeling functions always returns a tibble with a single column depending on the type argument
Kernel feature maps functions are now organized as kfm_nystrom(), kfm_exact() with a build_fm() method.
Update MilData class to mild_df class, and improve the class methods and constructors.
Many internal methods removed and restructured.

Initial release. This release has several known bugs and an early input/output scheme that has since been revised. This represents a mostly working starting point.